Hi Terry,  It depends on how many times you hit your wedges. Bob has added a heat treatment to the new TX3 hitting grooves of the SM5's to help it be more durable.  If you practice a lot out of the bunkers, the new wedges last twice as long as a non heat treated wedge.  The treatment will last and keep about 3/4 of the spin up to almost 1000 bunker shots. 

On Tour, players using 46° to 56° will change every 4-6 months, but they will change their lob wedges about every 4-6 weeks.  Some will keep a wedge longer if they feel it is still working well for them.  If you feel your wedges have lost their bite, it might be time to look into new ones. 

As far as sharpening grooves, the original grooves of the SM5 are very close to USGA tolerance.  In fact, we inspect each and every groove to make sure they are in tolerance.  100% of the grooves on every wedge are measured.  It is possible somone could sharpen the groove and have a precise measuring device to make sure they still conform, but it would be difficult. 

Cathi is right on the mark as usual!

I was with KB recently and he was explaining to me he gets new wedges almost every month for his bag to ensure he has the most spin possible.  Furthermore, when I was with Bob Vokey a year ago during a fitting he also said the same comments updating wedges that Cathi reiterated.  As a result of my conversation with Bob, I purchased a couple sets of wedges, one for more practice and one for competition...the specs are the same but at least I can rotate clubs to keep the same set for at least one season before updating my bag.  Never would have thought I would need to replace wedges frequently but I suppose it is just part of the sport! LOL

On a sidenote, I would not consider re-grooving my wedges...too many issues to deal with as Cathi pointed out already.

Hope this helps!

Terry - from talking to other "regular" golfers, it seems most get 1-4 years out of wedges before they see a need to have them replaced.  It all depends on how often and what type of lies you hit them from.  The new SM5s should last longer than previous generations.  For me personally (and probably a lot of average Joe's out there), I will "want" a new wedge before I actually "need" one.  As for sharpening, I looked in to this when I was looking for new wedges.  I thought about buying used wedges for cheap and refurbishing them myself.  But if you think about it, the wedge wears out because you are wearing away material from the grooves.  Once that material is gone, you can't put it back.  You can sharpen the grooves by taking more material away, but then you risk making things worse or potentially illegal.  Maybe it's possible for an expert club maker to properly refurbish a wedge face, but I don't think it's worth the time or effort.

Thanks to everyone for their comments concerning the SM5 wedges. It makes sense and I feel more confident about the wedges I have that I will not have any problems in the near future.