You stop losing canned goods in the dark back corners the day those pull-out pantry drawers go in. The actual install usually takes just a day or two, and booking it during the winter contractor slow season is the easiest way to get a better rate on labor.
Get at least three quotes from local cabinet folks before you sign anything. Prices swing wildly for custom work, and having options keeps you from overpaying for the hardware and the install.
That 0% intro period is a hard deadline, not free money. If you still carry a balance when those 15 months are up, interest kicks in on the original amount from day one.