Anon with 50+ dresses here, thought I’d give you another perspective.
You honestly wouldn’t recognise half my lolita wardrobe, it’s solids, non-prints, IW florals and plain Moitie. In fact, when I first started lolita I couldn’t even attend enough meets to justify maintaining a wardrobe of dresses I only wear once a month, so my criteria for adding dresses was (still is) that it could be dressed down and worn nearly normally as well. Bonus: these dresses are usually pretty cheap because other lolitas aren’t really impressed by them, so it wasn’t hard to get a collection going, either.
Basically, I don’t wear lolita everyday, but I do wear lolita dresses nearly every day. The plainer goth or classic pieces for work, and sweet lolita for weekends. Helps that I live somewhere fairly nice and my workplace is casual but nicely dressed. That’s how it’s easy to cycle through 50 main pieces a year. Add to that the climate, yoyo-ing weight, the odd dress you keep around to twin with your bestie/themed meets, the pieces you love too much to sell, whatever, I can see myself climbing up to 100 pieces in a few years if I allow it.
Thinking about the blouses too, and I think some other anon had a much better idea than an absolute number. If a dress can be coorded in three different (lolita) ways, then the number of blouses for it is good, so if all the dresses in my wardrobe can be coorded with three different blouses I'd probably call it good even if the dresses still outnumber the blouses. I have a feeling I really do need a few more blouses, though, I added a couple more green dresses recently but still only have the one green blouse between 5 dresses. I'm not always into matching 100%, but it'd be nice to have more than one green blouse to reach for if I want some variety.