1% chance and no backup?
That boss needs shooting..
Had a job on a customer's business machine. Minor 2 min fix. Probably a 1 in 1,000 chance something would go wrong. I took a full backup just in case, wasting a little over an hour of my time.
I needed the backup. Something a little more broken than I had detected, and a straightforward fix became a slightly different fix. 1st rule of computing, quick and easy jobs always turn into a disaster, especially if it's business critical or nearly home time/weekend etc.
(2nd rule - 1 in a million chances 'n all that..)