Use lifting straps only when grip would limit your performance, typically at 8/10 effort or higher. That means heavy sets of 2-4 reps or 6+ reps where your hands would fail first. Heavy rows, stiff-legged deadlifts, and multi-rep conventional deadlifts are good examples.
When to use straps can be a little bit controversial in the sense that I don't want to be using straps all the time. I don't want to develop a reliance. When it comes to heavy rows, heavy deadlifts, I will use and coach people to use lifting straps. Usually the work needs to be an exertion of an 8 out of 10 or above. So either maybe a really heavy, hard working set for 2, 3, or 4 reps, or they're doing rep work, let's say 6 reps and above. Especially say on a stiff-legged deadlift or a deadlift, when you start doing rep work, your grip is going to give. But again, that or it has to be the exertion has to be 8 or above.
