Restoration increases value for certain pieces today. What types and will this last?
 

In many different fields of collecting, restoration increased the value of an item - for a time - only to have market demand return to rewarding original condition.

Pedal cars, actual cars, motorcycles, comics, even arguably baseball cards (T-206 Wagners were professionally restored), before professional grading which did not reward restoration.

So what fields of sports collecting currently reward restoration? Is this a positive from a hobby/historian perspective? Will this last from a financial perspective?

A lot depends on the level of degradation to the piece. In some cases, restoration would hurt the value, and in others, it helps.

Take Stadium seats for example... If the chair is thrashed, with flaking paint, loose parts, rust or wood rot, then restoration is probably advised.

If the seat simply has paint wear or more minor flaws, then restoration wouldn't be warranted. Most collectors prefer these things in the original state. So changing away from the original version should always be done as a final resort (IMHO).
It just depends upon the level of severity.

Hartland and Bobblehead collectors frown upon it and for most collectors,
any type of restoration is a deal-killer. Same for vintage Pennants. My gut feeling is that it's more acceptable with paper items, due to the fragility and greater potential for degradation, discoloring, tears, etc.

Just my .02... Also, you might get a better answer if you can state the specific type of sports collectibles you have in mind.

I posted a Reach Poster (July Pick-Ups) from 1922 that needs some work and it is something I am trying to figure out. Do I do the restoration or leave it alone?

http://www.net54baseball.com/showthr...=171603&page=7

Jim, I would get that poster framed as is...I would not try to restore it. As is, it looks great to me and IMO any restoration on that could hurt the value.

Great poster.
I would have it professionally cleaned by a restorer, but I would not have it restored. Paper Conservation, Alan Firkser, in New York cleans my paper items, removing dirt.
Where are the game used guys in this discussion? Jerseys, bats, etc., had these in mind as well.

Clip from the Canadian comedy show The Red Green Show showing how to restore antiques to raise their value.

youtube clip

Restoration
 

I had the same concerns when I bought this piece (http://www.legendaryauctions.com/Lot...ntoryid=158797). I opted to restore mainly because it had some rust on it and I did not want it to further corrode. Otherwise I would have chosen not touch it at all.

I also agree 100% with what Mark (perezfan) said above.