I like to keep an open reservation on a padded room , when it comes to collecting !
Seems like the kinds of stuff that have stricken my fancy through the years have gone through as many changes as I have .
Although I do like to keep an eye out & an ear to the ground (for other 'antique collectors' too) , the current Queen of my non-antique collection is about one square foot of wax paper with a black ant that was included in the process !
Sorry about the continued hi-jack o' your thread , d95 !
Getting back to your original title , as to hiring a professional .... well , I just don't know of any true pros who'll work for discount rates , except for very close friends/relatives & such .
Perhaps it might be best for you to establish your budget , then go from there , with whatever item(s) you are most curious about being at the front of the line , so to speak ?
One last suggestion would be for your parents to contact their insurance company/agent & inquire as to the type of specialist/estimator/appraiser that would be valid for them , in the event of an insurance claim upon all/some of the items concerned .