I have mixed feelings either way. But #1 yes you need to do something about it and glad your serious about keeipng the trans in shape. Too often people just forget the trans...

I would say if you have money and you are taking it to a reputable business to get it done, then yes, get the flush. When they flush it and put the new filter in, it really is better than any amount of drain and fill jobs because their machines filter the old fluid and push it back in with new until the inside of the trans is clean. This is the most important part.

I did my own drop the pan, put in a new filter, put it back, filled and drained two more times... The fluid is just now starting to get pink and will probably take another two drain and fills to get it nice and clean. In my honest opinion, it's not really worth it. I'm probably going to spend another 24 dollars on top of the 40ish + I have already spent draining and filling and replacing the trans filter. It get's up there in price... So why not do it the best and easiest way?

Side note though I agree with avguy I wouldn't just take it to a jiffy lube. Their staff is probably untrained for the most part, and the few that are probably don't care because they are getting paid rock bottom dollar for work and are just waiting for a dealership to hire them.. Definitely take it to an independent shop. The price should be roughly the same anywhere for a trans flush and you won't have to worry about a reputable independent shop putting in the wrong fluid, forgetting to replace the filter, etc. etc. Oil changes at quick lubes are bad enough. Transmissions are much more finicky about a job screw up breaking them.