Are adjustable leg loops actually useful? I rock climb, and ice climb some, and need a new harness. I'd rather have a less expensive and lighter harness with non-adjustable leg loops, but I've heard that you need adjustable loops to accommodate winter pants. Really?
If you are going to star on Biggest Loser and will melt 50 buttery pounds off your thighs over a season, or add 100 pounds, I recommend adjustable leg loops. Otherwise, probably not. Most harnesses with fixed leg loops use a Y-loop design that will expand each loop several inches, enough to fit over both summer and typical winter garb. Unless you are changing from a loincloth to a Michelin Man suit, I can't imagine a wardrobe switch that wouldn't work with normal leg loops.
Adjustable leg loops are desirable in certain situations, though these are likely rare for you. For instance, if you are changing pants while on a climb, you can unthread adjustable leg loops, and don or doff attire while remaining tied in to the waist belt. Note that this only works if you can completely unthread the leg loops, some leg loops don't give you this option. Also, if you are wearing big boots with crampons, you can let out the leg loops and put your harness on without taking your boots or crampons off. In simpler terms, adjustable leg loops are nice for multi-pitch alpine and mountaineering climbs. For your purposes, though, they are the dog that doesn't bark. Think about that. Next!