Using stop loss in ROTH with energy stock (DVN)

I've never used a stop loss and they're controversial. Some use them and I've heard others that say they have a few drawbacks.

This would be in my ROTH so there aren't any tax consequences.

Anyways I have a small DVN position and I'm currently up 15%.

I got to thinking today that if it fell, or really any stock for that matter, and there were no tax considerations, what the point of holding it to the break even or into negative territory would be.

For example, I'm up 15%. Why would I want to hold it to say -5% gain? Why shouldn't I get out with at least SOME gain, like say even 5% or something.

So would it be wise to add a trailing stop in this case? And how far below do you set it? Wherever you want?

Or is it better to just have a pre determined stop price to get out?

Like say if DVN hits $62 or something? My basis is $59

Thanks