I put a new top [pink wood or what is now called redwood] on an outside table.
It is now starting to check. I wood like to put some type of finish on


Stain is the obvious choice (something with UV inhibitors, and
'redwood' color, would be suitable). You probably don't want paint,
a nonporous layer of paint will just blister when the wood (inevitably)
gets wet, assuming it bonds to the wood at all.
I like to wire-brush exterior wood before staining; it makes the debris move
out of the grain. A vacuum would pull any loose material from the checked
regions.


I've seen a good paint-job last for many years - on a picnic table
under a patio roof, but otherwise explosed 4 Canadian seasons.
I've also seen stain that lasts only a couple years on a deck fence.
.. so I don't think there is one simple answer.
Personally, I like the weathered look on outdoor wood - as long as
it's solid. Some folks want it to look like their dining room set ..
John T.