When do pocket pairs stop being set mining?

[ahsfl]

Ok, now this is something that I've been looking at a lot because I'm playing a lot more hands recently. When do pockets go from being set mining to being playing the best hand. I used to limp with any non face pocket pair but I've been getting some effective use of playing 10s (from anywhere) and 9s (mid to late) strongly. Is this being too aggressive? Also at what point does set mining become unprofitable to call. Example, dealt pocket 4s utg+1, utg folds, I limp, 2 more players limp, button-1 raises to 5 times the BB, both blinds fold, action on me, is there enough dead money in the pot there to call even if I'm 90% sure the other limpers will fold? Should I even be limping with that small a pair that far up front? Any advice appreciated