Generally if you've got mead or fruit in your airlock, the sooner you clean it out the better, because in a standard airlock it's going to be exposed to oxygen, bacteria and possibly fruit flies, and you don't want this backwashing into your mead. I once had a small colony of fruit flies breed in an airlock that I ignored for too long (dark corner, didn't notice it) and the little buggers hatched and crawled out on the wine side! (where they promptly died and were filtered out with a jet filter)... And if it does collect mold or bacteria, remember, any smells that it might make are also exposed to your mead.
And the sooner you clean it out of the airlock the less likely it is to require scrubbing to remove scungy bits sticking to the plastic (although keeping a fuzzy pipecleaner on hand is never a bad idea).
And the sooner you clean it out of the airlock the less likely it is to require scrubbing to remove scungy bits sticking to the plastic (although keeping a fuzzy pipecleaner on hand is never a bad idea).