Used to, Lily.
Not just for the free tea & biscuits or that inner glow of feeling I MIGHT be making some use of myself, to benefit others.
But not nowadays, unfortunately.
I'm now a net recipient of others' kind donations. (Last hospital visit involved several pints/litres - 9 bags of the stuff - whatever that is in gallons or plain English. Weirdly - I often find myself speaking with a broad Norfolk accent - laced with Brummie and Zummezet. Odd - but at least I survived to tell the TRUE tale.)
With various 'body parts' under serious review - suspected of carrying more diseases than the medics have yet found names for - I cant bequeath bits of my mortal remains to some other innocent recipient who might 'reject' them for very good reason.
ALL OF WHICH IS, of course, TO SAY - YES, IF YOU'RE FIT AND MINDFUL ENOUGH - DO IT !