I think that response times do vary by type of property; are you running a site with 200 apartments all together, or are you managing 200 single family homes all across town??? If you are in the latter category, you need more than a handyman kind of service response. You need a 'black book' of sorts, filled with outside contractors that can respond at a moment's notice, at any time of day or night (plumbers and electricians primarily).
If you are in the first category, you need to have a maintenance team of 2, who settle between them who is to handle after hours emergencies (switching off a week at a time for example). Maintenance issues should be categorized as follows:
Emergency: Fire/Flood/Blood/Electric outlets throwing sparks, gas leak.... have resident call 911 first, then your team.
Emergency: Lock out with child inside and food cooking (I just don't get this one, but I have heard of it happening).. IMMEDIATE response. You can eliminate this by having locksets installed that actually require a key from the outside to lock.
Critical: Toilet clogged in a 1 bathroom unit??? 15 Minute response. Have the resident turn off water supply behind the toilet to minimize damage.
Critical: Heating/AC not working properly...2 hours MAX (less if you are a senior property and there are health issues to consider)
Critical: Electric issue not caused by resident's failure to pay their bill or a larger cause outside the property. 15 minutes. You can eliminate the occurrence of utility shut off, by establishing a 'continuous service agreement' between you and your utility provider, Such an agreement will keep YOU informed if a resident has not paid their bill and gives you an opportunity to intervene and collect the past due amount.
All other maintenance requests, I would establish a 24 hour response time as an actual policy. In the event a repair takes more than 24 hours to resolve, you really need to take the extra steps to document the reason(s) this is the case.
Did I miss anything???