how long do you keep your old correspondences, letters, photos etc?

I still have all letters from the past, old photos, etc. in various shoe boxes, etc. i only seem to look at them when i'm tidying or moving house nowadays.

Do you still keep yours?

Also in similar boxes, stuff from holidays/travels (including travel maps/brochures/gig tickets/flight ticket stubs). Still can't bring myself to throw some of these away.

I'm fairly ruthless about pruning away old detritus. The largest exception is photographs, but that is because the great majority of my photographs pre-date the digital era, so they are not especially numerous. Even then, I am certain I could decently prune away nearly half of them, should the need arise. (btw, always make notes on the backs of photos, if you possibly can: dates, names, places - this doubles their value to you and makes them less of a cipher to your heirs.)

There's a value in retaining some memorabilia, but only insofar as those objects vividly bring memories to mind. If handling, for example, a toy dump truck you played with when you were five evokes strong memories of that play, complete with old feelings of delight, the setting where you played, and the faces of playmates, then that is worth a great deal. Otherwise, it is worth exactly the amount of good it does you in your present life; either play with it, or get rid of it.

otoh, my wife has the problem of keeping stuff on the theory that it might do her some good some day. We have a basement. Believe me, this is a dreadful combination I would not wish on anyone.