So I am using shimano un73 (68x107) with 75's. The past week the non-drive side of my BB has been loose. So I went to the shop today, to find out that the shell is 70mm.

Will prolong use of this kill the shell, or continue to loosen?

I am thinking of just getting phil wood BB with the cups that fit 68-73mm.

Thanks for any advice.

Edit: two shops and no one has a 70mm in stock.