Responding to parent emails

[2catsfighting]

what would you consider a reasonable time to reply? I'm not asking particularly about your school policy, but more of a personal work/ life balance sort of response.
I'm asking because I have experiences of 2 extremes, with some teachers responding the same day, which worries me on their behalf, and on the other half being ignored.
I really appreciate the prompt replies, but honestly am happy to wait a bit, but don't know how to resolve the ones that I don't get a response to.

[BackforGood]

Everyday - I think it makes a big difference if you are talking about Primary or Secondary.
It's nigh on impossible to be able to speak to a secondary teacher via phone calls / the office, but in Primary schools there's much more likely to be a single office / staffroom / pigeon hole system, and, if it is urgent enough not to be able to go into a pigeonhole, then the office staff will know where that teacher is. In secondaries, a) it's the teachers that move round b) they often have departmental offices, so might not go into the main office or staffroom for a few days c) a lot more internal communication is done by e-mail (rather than trying to get all staff together for a pre-school briefing say) so they will automatically be checking e-mail regularly.
Also, statistically, far more parents will be at work once dc are in secondary, whereas a higher proportion will have at least one parent at home (or sometimes grandparent who is able to take up a query) when they are younger.