At the start of any resto I like to get a fix on whether and how the machine works. Where there are issues I resolve those issues to get the machine working 100%. Where the issues are associated with for example immovable steppers I resolve those issues one by one and they then count as part of the overall resto.
I then sequence the resto in steps as backbox, motor board, pf (lower and upper) and finally cab. I take this stepped approach so I can isolate any further issues post resto. Surprisingly enough despite a full resto new issues may arise as I think Stoomer has suggested so I prefer a stepped approach to localise diagnosis of those issues.