Just got back. I think your apparel choices will depend on your plans as well as the location of your AI.
We stayed at Iberostar for a week. Non-diving spouse. How I packed that was helpful:
1. Electronic/powered dive gear / masks in backpack with go pro, etc.
2. Unpowered dive gear in carry-on duffel (got checked on the way down, NOT on the way back, grrr)
3. Clothing in checked bags. 2 pr nice pants, 4 nice shirts, 3 spf 50 hoodies (baleaf), 2 dive skins, 2 scuba swim suits, 2 dress board shorts, 2 wicking t-shirts, 2 pair sandals (beach and dress).
4. Wife: 3 dresses, 2-3 sets of something she called "resort wear", 2 swimsuits, assorted shorts/tops, and a bunch of other girl stuff.
What we did:
I dived during the am mostly, had lunch with wife, then did activities with her - snorkeling, shopping, etc. Had a dry day and did a jeep tour to see the east side of the island and the ruins. Had a nice night out at Baccinos (highly recommended for reservations 20-30 minutes before sunset). Did 2 night dives and a night snorkel.
What we learned:
1. American sucks for carry-on restrictions (confirmed). Packing a roll-on with the same dimensions as a duffel is the way to go to avoid issues, and packing MORE bags with more net volume > less bags. Stupid, but okay, fine. American staff don't understand the real size of their bins. Flight down took off with enough extra space in the bins for my 6' 225lb self to ride up there comfortably stretched out.
2. Wife says leave the resort wear at home, don't pack sleeveless tops if you aren't already tan, pack more dresses for the evenings, and spend the morning on the beach making friends with the other scuba widows. Non-nice T-shirts and shorts at the restaurants we went to on site play heavily into the ugly american perception.
3. I should have packed 1 more spf 50 hoodie for wearing on snorkel trips/diving boats then wearing it around the resort during the day before dinner. Could have gotten by with 2 nice shirts, 2 wicking shirts, and about 5 pr shorts / board shorts total.
4. Jeep tour after the $150-$200 credit for the timeshare pitch was a fair price because it included all the entry fees and lunch (grouper fajitas) was some of the best fish we had on the island.
5. DSMB in the BC pocket was the way. Never used it, but never worried on dives because I knew I had one and knew how to use it.
6. Need more bolt snaps.
7. Needed a better light, so I bought 2 when I got home.
8. We really liked the Kuhl roll-on zinc oxide reef safe sunscreen for the limited exposed skin area. Using the hoodies, snorkeling in my dive skin, and using the sunscreen just on my face resulted in 0 sunburn and 0 grease.
9. Bring sunscreen, aloe, etc. Really expensive on the island.
10. Now that we know the east side and island a bit more, renting a car for a couple of days will be good to do the east side and ruins more thoroughly.
11. Need to make reservations for pearl farm way in advance.
12. 1 dry day makes wife very happy and lets you dive 2x 3 dive days.
13. Flamingos are loud.