Sadly the word "should" ought to have appeared in your sentence.

A lot of resolvers ignore the TTL, either because of the number of misconfigured TTL entries (too short), because they resolve a LOT of names and figure they can't afford to keep looking up certain names, or out of sheer orneryness.

I don't update frequently so when I do plan to make updates I adjust my TTL to a short period, wait a few days, then make the updates, then after a week turn the TTL way up again. I've noticed that this is pointless with some big sites.