* fitted, not fired!

Correct. Fittings are for new equipment. You hit your existing clubs a few times against TrackMan and then they compare numbers against the new models set to your swing needs. Results will give you a good idea if you r current set up is good or bad. If they see much better numbers and are fitting you with different flex or lie, chances are those should also be what you should use on your older set.

Titleist Thursdays are typically for their current product line. If you know of a club/course close to you that is having Thursday events you might try calling to see if you could book a spot to work with the fitter on your current clubs.

For the obvious reason of offering a $100 fitting for free, they only carry the current models for the fitting. The 915's are coming up on 5 years old. If you can catch a slow demo day you might be able to try a couple of shafts to compare to your current. Buying a new shaft is about $150 and the 915 now retails on used sites for $100 or less. You can experiment with the hosel settings on a driving range.

Titleist Thursdays will only have the TS line of drivers (definitely not the 915s) ... I'm thinking your best bet would be to go to a place like Cool Clubs or Club Champion.

However, given that the TS shafts will fit the 915 you may still be able to try shafts but bear in mind that the shafts in the TS series of drivers is 1/2 inch longer than previous models.

New models are what is being fit at a Titleist Thursday. You might be able to book time with a fitter to do a check on your specs, it will depend on how busy they are.