Hmmm, definitely something to think about. Also something I would probably want to do before I put my rig together and not something I decide to down the line.
Edit: Not so sure about this now after some research. Deliding and applying better paste does improve things a good bit but overall gains are more likely between 100-300mhz tops depending on my luck at getting a chip that OCs really well. And while I want to overclock this I'm not skilled or knowledgeable enough to really push the boundaries and rigorously test things. I'm more about getting a healthy but reasonable increase. I'm an amateur enthusiast at best.
For my 4790K it was just increase voltage, increase clock, step by step (benchmark, then adjust) until I got to 1.35V, 80C, or a crash. Then decrease voltage until I get a crash and revert to the last stable setting. I started at 4.5Ghz at 1.2V and increased .03V and .1Ghz at each step. I didn't bother with any other setting (since they make no sense to me). I use the Intel extreme running utility for the CPU settings and OCCT for the benchmark.
I have a decent chip. 5.0Ghz at 1.33V or 4.8 at 1.27V or 4.6 at 1.22V. YMMV.
I would say the super low risk zone is anything below 1.3V and never hitting 80C under load. If you can get a good clock at that then you are basically getting free horsepower. If your chip can do that at comfortable temps, there really is no need to delid. Anything near 1.4V is not worth the risks. There are times of great guides on YouTube. That's what I did.