My turbo bolts keep backing out. What should I do?

Replace whatever non mitsubolts and non mitsu washers you have. (Yes. Even ARP)

Use stock Mitsubishi bolts and turbo washers. (Thanks Salomon Ponte) Also make sure to use Nickel based anti seize on any bolt you put in.

If stock bolts break, they are easier to drill out than some of the stonger non Mitsubishi bolts.

With the extreme temperatures these bolts see, if you want extra peace of mind, do not re-use turbo bolts and can replace with new Mitsubishi stockers every time you crack them loose to remove the turbo (not cheap! 60$).