For me, it's 2 DVDs (or CD depending on the size, numbers of pics). And to avoid the surprise that they could be unreadable in a few years (although it never happened to me yet), I am planning to copy all DVDs on an external hard drive. It might be too much, but I just don't want to regret I did not do it in the future

I also like to print some and show them in albums, old fashion but this is only a small selection of them