I have two 07 TT's. On one I changed the bearings at about 15K, could feel some minor dragging and catches.
On the other TT, the rear bearing failed at 6400 miles. Speaking from experience you do no not want a bearing failure going about 50.
Bearings are neither hard or easy to replace. You just have to know what you're doing. Heat works fine, but you should remove the drive sprocket and rotor on the rear. Its important that you heat the hub evenly. I use two propane torches and keep them both moving.
I made my own pullers. I turned a piece of about 4" long steel down to the bearing's I. D. Cut 8 slots about 3" each. I drilled a hole down the middle to the O.D. of an expanding concrete anchor bolt. I tightened the anchor bolt in the puller and once the hub is heated, poped the bearing out with a drift. You have to heat the hub enough so that the bearings come out with fairly light tapping.
The other method I use is with dry ice and 91% isopropyl alcohol. I make a dam of duct seal around the bearing and puller then fill the cavity with alcohol and dry ice. You have to keep feeding in chips of dry ice until the alcohol turns slushy. Once it gets cold enough the bearings pop out pretty easy. To install new bearings I coat them with cosmoline and shrink in alcohol and dry ice, again waiting until the alcohol gets good and slushy. Either way works fine but the heat may be little easier.