My Baa Baa is definitely quite durable but it's pretty thick – too thick for Summer use IMO.
Got loads of Merino stuff – T shirts, a polo shirt, jumpers, socks, etc – the thicker it is the longer it last but thin stuff like vests (use for running) and T shirts get holey very quickly. Mostly got Howies and Finisterre stuff – my Howies vest holed after three weeks, my Finisterre Ts did the same after two months, my Finisterre sweater (Coho) which I wore non stop as it fitted so well shredded at the cuffs after a few months.
Socks seem to last okay as do my "woolen" style jumpers and my Howies polo shirt.