We paid 50% up front and 50% upon completion of the countertop install. We were told most important that cabinets be level. If they had to do any adjusting it would cost extra. We bought our own sink and just gave the fabricator our sink and faucet so correct holes could be cut. Faucet hole was drilled on site but sink cutout had been done in the shop. Doesn't seem right that you'd have to pay extra if you don't use his sink-never heard that before. I'd be wary about that. How about getting recommendations from friends, neighbors, etc. who have had quartz counters installed. I would do more research before committing to this guy.

We paid 50% up front and 50% upon completion. We bought ours thru our KD so we probably paid more, but she took was responsible for everyone being satisfied on the install - on both ends. Our agreement was pretty general - how many sf over such and such surfaces, window sills, edging and pattern were identified but nothing else.

I would probably not pay more than a 50% deposit on any ordered material, counters, cabs, etc. 50% usually covers the vendors cost if the buyer bags out. Keep looking for someone that is more reasonable.

When we updated my MIL's kitchen in January, we paid for the granite in whole and gave a $1000. deposit toward labor at the time of signing. The remainder of the labor was paid after installation. Since her back splashes are granite, there is more granite on the walls than on her counters.

I agree with chris and the others and my experience was more or less the same as theirs. I felt financially protected throughout my remodel. Try and find someone else. This doesn't sound good. The sink issue really bothers me. Doesn't add up! Trust your instincts... Good Luck!