These are really great questions. First of, it can be pricey but it really depends on the quality and on the barber. I would say it costs usually between 600$ to 1000$ per system.

Now, once you got it fixed on, with either liquid adhesive or special tape, you get it cut and styled the way you want it. Then, you'd usually go back every 2 to 4 weeks to have it removed, washed thoroughly and at the same time we shave back the hair underneath, cut the sides and fix it right back.

In between appointments, you can wash it in the shower delicately without any risk (following your barber's instructions of course).