For regular trail and singletrack use, or downhilling?
For regular stuff I’d look at skills rather than pads, if in particular cornering skills if you are washing out on corners and grazing your arms. This is what was happening to me. Investigation on skills (with help from Jedi in my case) has me no longer losing it and sliding on my side when cornering.
Landing on roots, done many times though usually on the chest. Again, some skills work has cut down root trouble.
Anyway with the skills sorted, elbow pads would be in the way for my regular riding and not really required.
Downhilling though and I’ll stick some armour on there, just because at high speed, messing up and crashing hard on any extremity is worth a bit of protection. POC Bones by the way. Far too bulky and stormtrooper for regular trail use. Has taken hits well on DH days though.