I've recently bought a new 10TB drive intending for it to be the new parity drive and I'm almost at the end of the first full pre-clear cycle which I'm estimating to complete with a total of 51 hours.

I have read that 3 cycles should be a good stress test to catch a bad drive. My question would be, is it ok to skip the pre-read, or post-read, or both for the subsequent cycles? I do want to test this drive enough that if it fails, I could have it immediately replaced within its two week immediate replacement window.

Well the only thing is that it'll test it less... probably better to do 2 full cycles than 3 half ones taking about the same time. 

The first cycle is about to finish and it's the full pre-read, zeroing, post-read run. After some time it started to make sense that I should not at least skip post-read.

 

Am I right in thinking that the pre-reads after the 1st cycle doesn't really do much aside from additional testing? Since you just finished the post-read from the previous cycle, it seems like it makes sense that you could go to a write process instead of another read process. I don't know what I'm talking about.

Yeah I agree, I do usually skip pre-read too. Post-read is useful as it checks the write was OK.

Pre-read might be useful on old / used drives in the sense that it might detect bit rot / bad sectors that were never accessed and revealed before and if it already fails there no point bothering with the rest...