What would be a good name for a job schedule?
It seems to me that using a job name in the schedule name prevents it from being re-used, so I've chosen to focus on a shorthand for the schedule contents. I'm now using the following naming convention:

times per week - days of the week - run time


So for the examples in the question the new names would become:


Run every night -> 7xPW - MTWTFSS - 22.00
Every 4 weeks on Monday -> 0xPW - Mxxxxxx - 6.15
21.00hr -> 5xPW - MTxTFSx - 21.00
DAILY (which then runs only 6 days a week) -> 6xPW - MTWTFSx - 0.00


This seems to work for now because we have lots of weekly and once-a-day jobs. I'm not utterly happy with the 0xPW for schedules that occur every 4 weeks or monthly (what are we gonna do with the job that runs every 4th day of every month?), but it's not a big deal and the 0xPW at least tells us to look to the description for more info.

The daily jobs that run every xx minutes are not straightforward to name in the above manner - although 2016xPW - MTWTFSS for a once-every-5-minutes schedule is pretty telling.