Squealing chevy tahoe belt

No, it is not acceptable. That remark sounds as though it came from a service writer.

I have a 2002 Tahoe with 126k miles and never had a squeal from anything. (Perhaps just lucky)

Perhaps the A/C is squealing. You can eliminate this possibility by turning the defroster on high or turn on the A/C itself on high. If the pitch in sound changes or goes away, you MAY have found the culprit.

I emphasize the word ‘may’ as the engine takes more of a load while the A/C is working and may detract from another source.

To check for pulley alignment, use any straight edge (ruler or yard stick, etc) place against the face of two pulleys at a time.

Try this: take a water spray bottle (the type with a trigger) and while the squealing noise is present, squirt a LITTLE quick stream at the point where the pulley shaft enters the suspected unit. Do NOT saturate it.

If the squealing stops, that MAY be an indicator of a bad bearing.

FWIW, that is a very expensive method of tracking down the source of a squeal.