I use about 1/2 roll of solder per decade, but it's the good shit, rosin core Kester 60/40. I've still got a few Radio Shack Iron coated Copper tips for my Craftsman 42 watt iron. For me, at 61, it's likely a lifetime supply.

For personal use, always wash your hands after handling it, and try not to breath the rosin flux fumes, which are the real danger, IMHO.

For new designs, or anything mass produced, use the lead-free stuff, for Mother Earth and the rest of us. You really don't want new places like the East Chicago USS Lead Superfund site[1], 10 miles NE of me, to be created. The topsoil there was 0.1% lead! In doing family genealogy, I found that one of my dad's uncles likely worked there as a "Lead Burner", whatever that is.

[1] https://en.wikipedia.org/wiki/USS_Lead_Superfund_Site

Solder likes to spit tiny balls everywhere. When cleaning the tip you can even wind up with a fairly fine dust. I do not want lead dust around.