imho, unless your playing your tube amp all the time, it may not need to have tubes replaced once a year.
Two of my amps are tube amps. One I got new, one used.
The used one is now 4 or 5 years old. I replaced the tubes when I got it. Itās one of the ones that is self biasing. So pretty easy to just R&R them. Plus, thereās only 2 tubes so didnāt break my bank account. Them tubes are still in use 4-5 years later.
The other amp is 3 years old. I got that one new. Iāve not replaced the tubes in it. It sounds fine and performs as I think it should.
I have considered, and may take both to the shop for inspection though. As I am aware that tube amps do require periodic service. Bad part for me is, the shop is 50 miles out.
Since Iāve never bias my one amp, I donāt know, but I thought ya biased tubes after they were installed in the amp. Each tube is slightly different so ya need to set the bias after ea. tube replacement. I could be wrong of course.
I think ya need to know where to check voltage at inside the amp. If ya know that, it donāt look so hard to do, if ya know how to do it and have the proper tools. And, what not to touch while the amp is live. Thereās 420vdc round abouts when a tube amp is in operation. Touch the wrong thing when itās live, and ya die. So ya need to be aware of whatās happening so as not to hurt yourself. I donāt know enough so feel itād be best for me to spend money and have a electronic specialist do the work safely, and properly.
Thatād be a good consideration. I donāt think tube amps like to be dropped.
Solid state are much more robust it seems. One of my solid state amps has a dented corner. No idea how it happened, but it musta took a pretty good hit to dent the corner of it.
I did have to service that amp, but it had nothing to do with the damage to the cab. It had a broken pot that I personally broke trying to get the knob off of it. My error.
There are some pretty good sounding solid state amps out there imho. Iād surely consider them roland jc amps. Or, Iām more than satisfied with my peavey transtube bandits. They outright sound good to me. Not as good as the tube amps, but pretty darn close. Close enough that I play them all the time.
fwiw. I rotate through my amps. Today I play this one, tomorrow, that one. I think solid state has itās place for short play periods too. If Iām likely to play for 5-15min or the likes. Iāll use a solid state amp so as to not be turning on and off a tube amp.
Anyways, yaāve got time. Itās on your side. Use this time to do much research as to where ya wanna go. Amp, guitar, pedals. I did the same as your doing. I spent many months doing research in where I wanted to go, before spending any of my dough. fwiw, I also didnāt land where I thought I would have. This was after I played some different gear at the music store and experienced them. Ya may wanna head off to your local music store and give some gear your thinking about a try, see if it really is what your wanting to acquire. Ya may end up in a different place than you think you will. I did. 
Have fun in your adventure! Turn up the OD pedal. 