[Boatanchors] need to replace?

[corner five]

hi all,
I'm starting into my first tube rebuild project.  This is a nice old 
Heathkit signal generator model IG-102.  It appears clean inside and out 
and may  require some of the standard component replacements.  I do know 
that electrolytic caps do not age well and these will likely need to be 
replaced.  My question is around the other parts.  What are thoughts 
about best practices regarding replacing resistors, inductors, tubes, etc.?
.
I have the test tools to check both LCR and ESR (including in-circuit) 
values.   However I do not have a tube checker and do not know how to 
verify tube wellness.  I chose this unit to restore because it is 
relatively basic (compared to a transceiver), there is documentation 
available, and I also need my first signal generator.
. thanks.