I think it means different things to different people.
A thing that I enjoy doing is going to YouTube and watching videos put up by "mikesradiorepair".
For the most part, when he does a restoration:
a) it always includes a complete and total replacement of all electrolytic caps and often some of the tantalum caps. Then, generally removes mods that were done in a manner that hurts the operation of the radio (of course he DOES talk to the owner and tunes WHAT he does to WHAT they want). Essentially his goal is to get it back as close as possible "electronically" to the day it came out of the box. Then does an alignment to get it back in to spec. He is not one to push radios to a dangerous point to get that last .78 watt.... rather he is a believer that if you set them up the way the designer intended the radio will "work fine, last a long time, guaranteed not to rust, bust or collect dust"!
He is not against putting in something like a VFO based expander... he just does it neatly without destroying the radio. He doesn't go ape on the cabinet/enclosure but he does clean them up, face plates, knobs, cabinets...
I enjoy his videos and you can learn a range of things. He generally does not "do the work" on camera... but he discusses the troubleshooting and how he determines what needs fixing.