I have two apps in the iOS app store. One launched in 2009 (Filer) and the other in 2010 (FLAC Player). I've been really lucky that both have done so well, especially 5 years on. I maintain them for major iOS releases and hardware changes, but the little time I have I try to work on new stuff and supporting them. My wife helps with support emails now, which has been a huge help.

Neither app has any server-side components, so they don't cost me anything but squarespace fees for my website and my iOS dev program membership.

Edit: Oh yeah, they're both paid apps and I don't fiddle with the pricing