Keef,
Funnily enough, a friend of mine has old-ish Apple laptop with a spinning platter drive.
She being a frequent traveller, and spinning platters being what they are, the inevitable occurred and the drive started becoming more and more unhappy.
Her backup regimen having been configured by me, she was running TimeMachine to multiple locations, but explicitly configured NOT to backup user-installed software or system-software.
New drive, OS X install, TimeMachine restore of files, re-download of a handful of apps from the App Store, Adobe stuff from Adobe, Office from Microsoft and a couple of minor utility apps from third-party developer sites ... she was back up and running within a day and a half (would have been quicker, the system and software was ready to go within the space of a few hours, but she had many many gigabytes of of user data... photos and whatnot !).
Quite frankly, even if I had it, I wouldn't have wanted to use a system image. The disk diagnostics were throwing up all sorts of scary messages, and by the time I got my hands on it, the system was running like a right dog. Restoring onto a new drive would have solved the hardware problem, but would highly likely have still left me with unhappy software to contend with.