Partly it depends on what the songs are.

If he was doing ballads, then changing every time was good idea.

However, bands which are doing jigs or reels usually string some together, say 3 jigs in a number.

I think people get tired of too much uniformity before they get tired of too much variety. One night I attended a concert where every number was in 4/4 time. I wanted to call out 'For heaven's sake, play something in 3!' but I didn't.

When I play with friends, we try to vary

timing - 6/8, 3/4, 4/4
major vs minor
speed
vocal versus instrumental.

Just don't get too wild about it. Don't follow 'Kilkelly Ireland' with 'Grandma Got Run Over by a Reindeer.'