Desire is clothing optional. There are many folks who choose to wear something at all times of the day and night and in all areas of the resort.
Lots of women are topless at the pool and beach, many are completely nude and there are quite a few who wear tops and bottoms.
Some folks walk nude to and from their rooms to the pool and beach. Most cover up, though.
Many men are nude at the beach and pool, lots wear some sort of swimwear, some men wear pareos (wrap-type skirts) as their coverups.
Wear clothes when you go to eat and want to go into the lobby area.
Lots of women dress in theme, some men dress in theme as well, depending on the what the theme is. It's difficult to say there is any sort of percentage. It varies. We have found lingerie night and school girl night is very popular (may cuz they are 'easy' themes to dress up for?)
Sexy dress (for gals) and "dress to impress" (for guys) for dinner (if you think your sexy dress is over the top, it's not - you will fit right in).
Many folks change a couple of times a night - sexy dress for dinner, costumes for themes.
But some folks wear their theme clothes to dinner as well.
We travel with carry on only and have no problem dressing in themes for every night of the week if we want to participate and we wear something different every night for dinner - you need very few daytime clothes and, dare I say it, I only take a couple of pairs of shoes. LOL!

Hope some of this helps.