I think this style isn't out of fashion as such, it's just not in fashion either! They aren't truly parsnip tight jeans, and there are still a few people around styling those out!
Slim jeans are more classic, so I'd put them with something fairly contemporary and not something a bit dated, for example, a short rounded edge tailored jacket might look old-fashioned, a larger baggier one might look great. I also like these with loafers, not trainers. Short cropped jackets are cool with baggier jeans.
I don't think you have to slavishly follow fashion, but if you dress from head to toe in things from 15 years ago, that does look dated, if you mix in the odd thing from your 'heritage collection' as I think of my jeans, with some more up to date stuff, it avoids this problem.
That's what I do anyway and no-one has arrested me for crimes against fashion. Yet.