Bringing along a spare gives you an opportunity to toss it to a friend who shows up at the pool and says he’d join you but forgot his suit.

I have never worn a thong on a water slide, but I always wear the skimpiest briefs I am comfortable with in a family environment. I have also done the tuck of the speedos into a thong trick, and once in Germany late in the evening when nobody was behind me waiting to slide I pulled the back of the speedos down off my butt entirely. Definitely slide faster with less cloth. I want to go to Miramar one day for their nude night where apparently you can slide nude too.

When I have a beach day I have a morning swim and an afternoon swim to avoid the hottest part of the day. I usually wear a different swimsuit in the afternoon simply because I have so many and I love showing them off.

100% the same for me! I have way more suits than I have a chance to wear!

I only have 3 swimsuits. One relatively heavy short shorts, one tan through short shorts and one tan through brief. That's enough for me.

I have a custom of taking a couple clean, spare pairs so I have the option to lend should anyone express interest. I've had a couple good experiences. Guess it pays to be prepared!

I only go to clothed beaches on vacation.
When going to the beach in NJ, if I bring a swimsuit, it comes off as soon as I am out of site of the road and that is all I wear when I get out of the car.
Other times, I will be wearing shorts and don't bring a swimsuit.