Re: 1989 RG 550 advice?
Eliminate every possible issue before investing in a new guitar, neck or fret job.
All screws tight?
Is it setup properly; string retainer in right position, nut height, truss rod, saddles in good condition, intonation correct, correct trem angle?
Can you hear it acoustically?
Can you hear it amplified clean and dirty?
Are your pots clean and working?
Is it all selector positions?
What is the distance from string to pickups?
Are you slapping the trem arm? (that’s a joke)
I think after exhausting all of these options you should have it checked by a pro. Most will charge you a bench fee that can be applied to any necessary repairs or adjustments.
I think it really depends on your relationship with the guitar. Do you have the money to spend? I’m not sure of the availability of necks through Ibanez these days, but there are plenty of people ready to do custom work.