Time for upper and lower ball joints?

[Altnrgy]

First let me thank you all for the great responses to my last question. I can't tell you how great it was. I look forward to being able to return the favor. I scanned the forum before I asked this question and even though I'm sure my answer is there I didn't find it so please accept my apology in advance.

A local shop is telling me that my 99 F250 2wd with 221,000 miles needs the original upper and lower ball joints replaced to to the tune of $675 parts and labor.

Two questions
1) Is this price in the realm of reality to a pay shop to do it?
2) Truck is tight (very tight actually), no funny tire wear what so ever, no rattles or squeaks and certainly no noise from the front end. I'm assuming these guys aren't slow and trying to make their next boat payment and that I can believe them. They've done some other work on other vehicles before and treated me right but....
Should I wait until a rattles appears then deal with this? No need dropping the money now if don't have to but I'd also like to just get it behind me. One important detail is the I'm getting new tires on in the next week so.

Thanks, Travis