I don't like having long fingernails. They just get in the way, or I scratch myself, or they are too hard to completely clean, or they make it hard to type, or they just look weird and feminine—take your pick from those reasons.
I clip my fingernails on Fridays. Sure, sometimes I clip them on different days, but it's usually Fridays. Why Friday? I play board games on Thursdays. Short fingernails can be annoying when
playing a game involving cards. I also vacuum my apartment on weekends. So, clipping my fingernails on Friday lets me have one-week-long fingernails (a very convenient length for card usage) on Thursdays, and it also allows me to just clip my nails sitting in a chair over carpet, because it's going to get vacuumed up really soon anyway, not having to deal with clipping them over a trash can or something awkward like that.
Just thought I'd share.