R57 All just IMO, and talking about the maximum I think its respectable.
If you're a teenager then do whatever. You're likely to experiment with lots of approaches anyway.
If you're a twenty-something, 5-10 years earlier, as long as you look mostly similar. That's if you're camera shy or private, because otherwise you likely have more recent photos to use anyway, right? And I really just mean that if you're around 20, high school photos are a little weird but not bad, and if you're nearing 30, early 20s photos aren't bad if you look at least around the same or better now.
If you're a thirty-something, 10 years earlier, again if you look mostly similar. In other words, your 20s, not high school or collage years. But if you use your more youthful ~25 year old self in a photo and I see you're 35 and still healthy but with more signs of age, whatever. Put your twink photos away.
If you're a forty-something, 10-20 years earlier, and you know the drill. If you know your 20s self is a far cry from your 40s self, then stop deceiving people. But if your 20s self was just younger looking but now you're healthier looking, fitter, happier, then I'll just question why you bothered with that 20s photo, but otherwise its cool. There usually isn't that massive of a change between one's 30s and 40s (the former might hold onto semblance of young adulthood and the latter may be accelerating towards senior life, but neither is guaranteed). Again, put your twink photos away.
If you're a fifty-something, 20 years earlier, and only if you haven't shriveled up by now. Lots of people can keep up their looks between their 30s-50s and so showing off a really nice photo from back then, that still doesn't look that different, is just a nice share instead of an illusion. But around this age is when so many would post their high school, college, or I suppose 20s photos is applicable here too, and that's just.. pathetic. Put your young adult photos away.
If you're a sixty-something, 20-30 years earlier. You're an old man now, stop reminiscing on your motorbike trips in their 20s and move on. Stop putting your childhood pictures on your profile. Stop pretending you're that model you were until your thirties. Just stop. Have an album available of it if you want.
If you're in your thirties and gained a lot of weight, but you're trying to make people think you're much thinner and in your twenties, that's not the worst case out there, its just kind of sad.
I put too much thought into this.
I have some of this issue I guess. I'm 31 and don't use my teen pics, nor around 20 or early 20s, but my mid-to-late 20s stuff because I rarely get my picture taken and I'm shy from taking it myself. I'd say I have above average natural features that I don't work the best with, and I'm considered tall and somewhat handsome though filling out a little, so I shouldn't be acting this way, but I do. I think I did react badly to gaining an average of 5-10lbs into my later twenties, which is nothing compared to lots of others' stories, especially since I actually like my aging otherwise (hairline receding but fine, a few stray greys look good, very light eye wrinkling is fine). I'm just self-conscious so I'm lazy about updating, but I don't try to be deceitful. People even still think I'm ~25 oftentimes anyway, when not right up to my face.