We get each customer to sign a terms and conditions before wrapping, we also take photos of all imperfections on the paint before wrapping to not only cover ourselves but also if the car comes back for removal you know of areas to take extra care with. We then give a care sheet along with the receipt/invoice.
Although we do the above it should be a secondary to the 'sell' itself. You would need to be having these discussions at the very start, before you get to any handouts. This is how simple it is for us to deal with all a few issues during initial conversations:
Us - Is there any imperfections in the paint such as rock chips, lifting paint, rust etc?
Customer - Yes there are....
Us - Basically anything you can see or feel will show up through the wrap. Although it helps make it look better it will still be seen/felt to some extent.
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Customer - Wow, that's expensive, maybe I should just paint it
Us - A common misconception is that vinyl is cheap, although 90% of the time it is, there are cases where it isn't. It was also never made to be a cheap alternative. It was made to protect your OEM paint and provide a removable option. The fact you can change colour at a cheaper rate is a credit.
If you want to paint paint, if you want to protect your current paint then wrap. What happens when you paint and then that gets scratched?
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Customer - How long does the wrap last
Us- Like the original paint it depends on how well you look after it and where it is stored. It has a recommended removal of 5 years but if it is poorly cared for it can be less than this.
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Us - Great you are booked in for XXX. Please make sure the car is dropped over with a thorough wash. Do not polish or wax. There is a charge if we have to wash.
Although the last one helps, a lot of people don't know how to wash their car properly and we don't expect it to be immaculate. Even if a car is immaculate we go through the same 3 or 4 stage cleaning process, just hopefully without a car wash....
Hope this helps, happy to provide a copy of our T&C's but again you need to do a lot of it before you get to that stage. also helps weed out the dreamers.
As always, undersell with the truth and then over achieve with the install!