If your irons already have Dynamic Gold, not a need to change unless you want to spend 30+ bucks a pop for Project X or KBS.  DG works fine and lasts a long time (and even new irons come with them as stock shafts).  Also have to add $20 per club for labor and the cost of a grip.   

The cost of a reshaft on the woods depends on what you choose for a shaft (about $14 for the bottom end to about $200 for an Aldila Voodoo).  A moderate cost shaft (such as ProForce) is about $65.  Being modest, probably want to estimateabout $100 per club on driver.

I'm also of the thought of "if it ain't broke, don't fix it".  

The main reason for reshafting is, IMHO, if your shaft flex has changed.

Hey Josh,

In terms of getting the best results, the latest technology will generally be the best in terms of getting the most out of it. However, if you are perfectly satisfied with the heads, then reshafting may be a good idea. A driver these days off the rack can range from 250-500. If you think you would spend that much on a new driver and buy it off the rack, I would caution you against that. Drivers sold off the rack are a bit unreliable. The shafts in them are sometimes questionable. I would spend my money on getting a high end shaft that can cost anywhere from 200-700. If you want my personal opinion on what the best shafts are, I can give you it, just know that this is what works for my swing. My driver is a 910D3 7.5 with a Graphite Design Tour AD DI-7 X. Its the orange shaft. This thing is unbelievable for me. But you have to find what works for you. Personally my opinion would be to put higher end shafts in the heads unless you completely want to get rid of the heads, which in that case, I would go and get fit for heads and shafts if you truly want to get the most out of your game. Good Luck. 

If I am going to drop close to $500 on a new driver, $220 for a new fairway wood or hybrid, or $1000 for irons, I plan on doing the whole fitting process.   At this point I know my set makeup, my shaft lengths and lie angles and the shafts that have worked.

Unless you are dealing with an apples to apples comparison, shaft, grip, swing weigh, length, lie, ball, hitting conditions, there is no way you can objectively compare new equipment to old equipment with new shafts.  Every shaft, head, is different, even with the strict quality control from most manufactures, there is some variance that can make a certain combination better or worse.

for your situation, what are you trying to achieve?  Can a driver head from 4 years ago with today's shaft be just as good as something off the shelf, yeah it could be, but I can bet you that if you tried a new driver from different makes you can find one that is longer, straighter and more forgiving than your old driver.

But in the case of irons, are the new irons that much better than something that came out 10 years ago, probably not.  I hit my new Mizz JPX 800 no better than my old Ping i3, nor do my Ping G20 seem that much more forgiving than my Cally X-14 PS.  .  Even if i took the most optimized shaft for my swing and put it an old set of irons, i doubt i can tell the difference in performance.  Obviously if my old shafts were X100 and i was optimized for R300 things would be different, but generally speaking all the new shaft technology in irons hasn't come gone as far as driver and wood shaft technology

I would say, if you are happy with your old gear, keep it as is.  if you want new shafts don't bother, just get a new set.

What kind of clubs do you have? What do you want out of your new shafts? Higher ball flight, lower, spin, control, etc.?