For most reloading you want consistency. I would divide them up by what you know to create a "lot" based on brand, and maybe go further to storage condition. Some loads in my experience aren't sensitive to primers as much as powder and bullets, but some load are and a primer change makes a bigger difference. There is a bit of trial and error when swapping from one brand of primers to another. If I swap primer brand, I always start low and work up. In some cases, not all, the node for grouping can be similar or even the same if you swap primer brands. But for safety don't assume they are interchangeable, even though you may find they are pretty darn close after you work the load from bottom to top on powder charge.
You can put a primer in an empty case to verify it will go bang in your rifle if you suspect they are damaged. It's much better than dealing with a squib load.
Primers are pretty resilient so unless you suspect they got wet, I personally wouldn't sweat about it too much.