How far to upgrade critical factor in labs?

My lab critical factor is at level 57 rn and I'm wondering if I should keep that permanently running or if i should stop critical factor at some point and swap it out for something else. obvs attack speed is also always going in labs

I'm a health build rn with about 30 billion lifetime coins so I'm definitely no where near being a damage build but that doesn't mean I don't need critical factor, right? Especially for those dang protectors. How far should I take critical factor?