[morzh]

Joe

often times I do the same, but there are places where a resistor to be within tolerance is more important thn in others (like, to me AVC being 2M or 2.7M would not even make me touch it; this one is in series with the Control grid, so the drop caused by even a small current can affect it) and so some resistors I correct and some I do not.

Those that I do correct, I either replace or parallel.
Those I parallel are the ones that went outside of tolerance but within reason considering the age.
2.7M vs 2M is within reason to me, over 90 years.
Within reason means speed of change. This one went up 30% over 90 years., or 0.33% a year on average.

Then let's say it went to 4M/5M. To me this is bad, same as if it were open. I will yank it and change it.
Another possibility if a large resistor went up so much, that you could parallel the intended value resistor to it (say, 10K went to open or 100K and you parallel a 10K there) and hide it behind the original resistor. Sometimes I do that too.