A colleague / client sent me this question today:
How would you explain the spelling of <lair>?
There is no word <lare>, though she had located a Latin plural loanword, Lares, but that is not actually a homophone of lairs; it rhymes with Larry's, not lairs. She also suggested that perhaps there's a relationship between the <i> in <lair> and the <y> in <lying> (as in lying down, not as in lying through your teeth). That's a workable idea: related words can and do have related spellings.
I always appreciate it when a question comes with a hypothesis, even if it's not 100% accurate, and when the asker shows her work. This client's expectation that the spelling is etymologically driven is accurate and well-informed, and the Etymonline entry for lair indicates that it is "[e]ssentially the same word as layer (n.), but more ancient and differentiated in sense." But there's more depth and clarity than that. I'm glad she reached out with her question, because it gives me the opportunity to remind everyone about the etymology not only of words, but of spellings.