[tor-relays] Question on relay allowed downtime

Hello,

So recently I had an uptime of about 3-4 days but then I had to restart my computer to install an operating system update (the OS in question being Mac OS X High Sierra). I know I am not to worry about what flags I have as long as I am not a bad relay, but am curious, what is the allowed downtime the network allows to do things like install operating system updates, etc, without significantly impacting time between failures?

Thank you.