Yesterday Edgar wrote the following on my Facebook page and while I answered his question, I felt like it deserved a fully thought-out response:

Today I'll be sharing what lenses I use during distinct portions of a wedding day (preparation, reception, ceremony, etc). I'll be walking through the process in which my mind works (minus the thoughts of glitter, temptations to dance, and the constant desire for dessert) in relation to what I'm carrying with me. As I've mentioned before, JD and I transport all our gear in a large backpack. We also use smaller bags to carry the lenses we'll need just in a specific time of day.

PREPARATION
JD documents the groom getting ready and I document the bride getting ready. In light of not shooting together, we open our backpack and load our smaller lens bags with the gear we'll need to document this portion of the day. We need to make sure we have a wide array of lenses, and we opt for prime/fixed lenses so we can shoot with wide apertures in low light situations (most hotel rooms have limited light) without the need of flash.
Lenses I carry with me:
35mm f/1.4 – this wide angle lens is great for capturing the entirety of the room while the bride is getting ready as well as lounging prep photos of the bridesmaids in small groups.
85mm f/1.2 – this lens is traditionally used to capture portraits of the bride as she prepares and her bridesmaids as they look on from a distance. The 85mm has a lovely photojournalistic appeal, so I love standing at the farther point in the prep room and shoot with a wide aperture so the bride is in focus and items/people in the foreground are blurred.
50mm f/1.2 – this lens is the most versatile in my opinion. It's not as wide as the 35mm (which sometimes can include things like cluttered hotel corners or messy wardrobe explosions), but offers more latitude than the 85mm (and focuses faster too!). I use the 50mm to photograph everything from prep, candids, the bride getting dressed, and details.
100mm macro f/2.8 -this lens is great for capturing small (but important) details like the wedding rings, beading on a dress, or small sparkling details (like a crystal on a wedding invitation).

CEREMONY
I arrive to the ceremony location about 30 minutes before it starts so I can document the location unobstructed by guests, clothing, or purses that can sometimes weaken the photograph. During this time, I load my small bag with the lenses I'll need to document this portion of the day.
Lenses I carry with me:
70-200mm IS f/2.8 – this lens is my ceremony go-to lens for weddings with more than 75 guests. The goal is always to go unnoticed by wedding guests, so I try to remain at a safe distance from the bride and groom for most the ceremony. This zoom lens is great for close up photos as well as quick focusing abilities as the bridal party and bride walk up the aisle.
35mm f/1.4 – this lens is great for an overview photo of the ceremony location and guests seated during the vows. It really helps set the scene of the ceremony and helps tell the story.
50mm f/1.2 – I keep this lens on me in case I'm in a pinch and someone asks for a portrait. It's common for guests to want to be photographed or a family member requests a quick family photo, so in these cases, I'm prepared with a lens that is great for this request.

PORTRAITS (family, bridal party, and bride+groom)
The goal for me during this portion of the day is to stay on my toes and have a myriad of lenses that give me the latitude to quickly change given the size of the group I'm photographing. For instance, family photos can range from 35 people in one shot and 4 people in the next. I don't want to use the same lens in this situation, so I carry lenses that will quickly offer variety. When it comes to photographing the bride and groom, I use the 50mm, 35mm, and 85mm extensively as they reflect my style and vision. More details and explanations here…
Lenses I carry with me:
35mm f/1.4 – this has been my go-to lens lately. I love the width of this lens (it closely captures what the natural eye sees) and it works well for groups ranging from 2-9 people.
24mm f/1.4 – this lens is awesome for large groups. Any group with more than 10 people is mostly documented with the 24mm, although I must caution to allow space at the edges of the photo because this lens distorts at the edge. You don't want Auntie Mae complaining that her booty looks twice as big as normal on account of your photography, right?!
50mm f/1.2 – I occasionally use this lens for portraits ranging from 1-2 people. It's great for bride and parent combinations, as well as groom and each groomsmen combinations, and it's a solid lens for bride and groom portraits.
85mm f/1.2 – JD uses this lens quite a bit during portraits because he stands at a distance and captures candid moments that occur during my placement of pairings/groups for formal photos. This lens is great for capturing that stolen look a bride gives her groom, a flower girl adjusting her flower basket, or the ring bearer crying in the arms of grandma. As a second shooter, JD is great at anticipating (and capturing) these moments.

RECEPTION
I adore prime lenses at the reception because they offer so much latitude in low-light situations. I usually shoot a mix of photos leveraging flash filled and ambient light photos, but I personally lean toward ambient lit photographs. It has a more natural appeal and an authentic vibe to the reception, but I also use flash in case the creative team (florist, venue, coordinator) prefer traditionally illuminated photos. I also have an off-camera light set up (you can read more about it HERE) in the corner of the room and it offers just enough light to create the dimension I love in usually dark photos, especially during the first dance.
Lenses I carry with me…
35mm f/1.4 – this lens is great for a reception overview photo (where I clear the room to get an unobstructed view and no one in the background), as well as using it for the grand entrance. When the bridal party is announced, I love focusing on the subjects, but also love the story told around their entrance, which is usually happy guests cheering them on. I also use this lens for a portion of the first dance for a wide angle of guests watching the couple and story surrounding their beginning moments has husband and wife.
50mm f/1.2 – I use this lens quite a bit for detail photos (head table, individual tables, centerpieces, the wedding cake, toasting glasses, dessert bar, seating cards, etc) as well capturing candid photos during cocktail hour when time permits. The 50mm is also great for the first dance when I want the focus to be on the bride and groom
85mm f/1.2 – I adore this lens for its ability to allow me to stand at a distance in low light and still capture what I want. The 85mm is golden during the father/daughter dance, speeches, and the first dance. There's just something magical about the light it captures and the bokeh it produces. However, because of its weight, I put this lens away in the backpack as soon as formal dances have concluded…that sucker is heavy!
24mm f/1.4 – this is my all time favorite lens for capturing party/dancing photos. Yes, photos of individuals dancing are important (and JD captures those brilliantly), but when guests are boogying on the dance floor, the story surrounding the dancing guests are just as important as the dancer himself. Reactions tell a much different photo and the 24mm is so wide that it captures this really well.

I hope this offers insight into my lens choice and work and I wish you all the best as you find the best fit for you along the way as well. To see a list of all the photography gear I use, feel free to check out this POST.
Stay Fabulous,
j*

**Edited to Add**
For those who asked, I shoot with one camera body (although we have backups as well) because I find it easier to cull my images after the wedding from a single camera, as well as working with a bad back (and, boom, now I sound like I'm 65). Carrying another camera would mean more weight on my back, so I've learned how to quickly swap out lenses…it takes no more the three seconds. Promise.
And we keep the large backpack hidden during the portion of the day we're not accessing it. During the ceremony, it's hidden under the gift table. During the reception, we make friends with the DJ and hide it under his table along with his gear. The key is to carry only what you need and hide the rest.