New strings? Used strings? Both?
Both. All are synthetics of one sort or another.
I have some that are brand new, backups of the current strings that are on my DB which I like a lot...
Then I have some that are new-old-stock that I liked but probably won't use again. I have some that are used that I liked but not enough to keep on the DB. I have some that are used which I really didn't like and will never use again. But I can't bring myself to get rid of any of these, sell, trade or trash.
It sounds like I've caught the DB SAS bug, eh???
The tough thing for me is that with any strings that I like well enough to keep using, I'm obsessive enough that I'll want to get a full backup set for them. That can get expensive, and that expense issue has in some cases prevented me from getting some strings in the first place. I may like the idea of using some specific set of strings, but I basically don't want the expense of buying two sets of them.
Also, some synthetic strings do not re-string well. Windings can break, cores can break. Fear of the unknown, I guess.
I think I am lucky to have only one DB. To some extent it is self moderating.