I agisted my horse 30 minutes from me for a week when I first bought her because we were in the process of putting fencing up on our land. Wasn't fun and I don't think I'd be prepared to do it long term, as I will always do all my own care and rug 24/7 so need to go out at least once a day, preferably twice.
I then had my horse on our land, which was a 2 minute drive from where we were living at the time. That was really easy and I always went out twice a day.
After that I had her at home which was obviously the best, but I didn't mind when she was a quick drive away either.
I don't currently own a horse but am looking to buy again relatively soon. I have moved interstate since I had my horse and no longer have land so am going to have to agist. All the places I am looking at around a 10 - 15 minute drive. I wouldn't want to go any further away than that, and I'd definitely prefer to agist within 5 minutes or so from my house, but you do what you gotta do and I'd rather have a horse I have to spend 15 minutes driving to see than no horse. As far as lessons go, 45 minutes - an hour is about as far as I would go on a regular basis, especially if floating a horse there.