When should I replace tubes and/or get a checkup?

[SonVolt]

So I bought a 3 channel triple that's prolly a 2004ish model, traded my 6505 for it. how do I know if it needs new tubes? Especially since I don't have a reference point for it since I haven't owned one before to know if it's sounding 100% like it should.

 

[R_ADKINS80]

Well preamp tubes don't really "wear out" they either work or they don't. Power tubes on the other hand can get weak. If it were me I would put fresh power tubes in it, just so i know they are new, and leave the preamp tubes alone unless i wanted to change the tone.