I'm so tired of colleagues and managers never replying to emails until days (sometimes weeks) later, usually with the excuse that they have hundreds of unread emails backed up.
I just think there's no need for it. Find a strategy that works for you and do it. Don't just let your emails back up without dealing with them. It's rude and it's counter-productive for both your own efficiency and that of the people you work with.
I know my own strategy wouldn't work for everyone, but I would never just ignore an important part of my work because I haven't taken the time to figure out a system for managing it.
AIBU or is it ok to just let your emails build up and up and leave correspondents hanging for ever for responses?