I think it depends a lot on the quality of the jack. For instance, I recall seeing a picture of a bunch of Skylab's portable amps a long time ago, and noticed that the jacks on his Hornet looked significantly worn. I've also read that the jacks on the Hornets were upgraded at some point in production, which is nice to know. I have a Hornet, and the jacks show no signs of wear. Just to be extra cautious, I minimize plugging and unplugging of things. The first thing I did when I got the amp was to plug my ALO Cryo Micro into it, and it has not been unplugged since, nor will it ever be since it doesn't need to be unplugged.
EDIT: Here's a
link to the picture I was talking about. Yes, it's just a digital photograph, and maybe it's the lighting or whatever else, but I think both jacks on that Hornet
look pretty worn out from lots of plugging and unplugging of things. I'm sure they're still 100% functional, so I'm only commenting on what they can look like after some normal wear and tear.