Last summer I did a subway tile surround, I hate the plastic ones, and only use fiberglass for shower stalls.

The plastic allows for some expansion.

As far as the mechanical work goes thats all on him. he will be piping everything to code (hopefully). if he asks you what type of material you would like to use on this project copper is best for water lines as for one copper joints are stronger than plastic and two copper is natural so your not drinking something that was sitting in plastic for god knows how long. now a days the go to is pex which is fine and also cheaper.

Most of the Keurig coffees taste very similar, which isn't very good, and I hate the cost and waste of plastic.

Remember to use a plastic chair protector for your office chairs as the casters WILL dent the floor...pads under the legs of chairs/furniture...If you were thinking of turning it into rental down the road, I'd go laminate in a heartbeat. 

They sell a little install kit that has a plastic block used to snap them together and a metal bar that you use for the pieces next to the wall.

Plastic coated cable works well.If the rope isn't on the window you'll need to pull off one side of the sash and pull the window out (lower part of a double hung) and screw in to attach the rope.Put the weights on so that in the full down position the weights are just below the opening at the roller wheel

Rather than using ABS (plastic) for the drains he installs cast-iron that has a life expectancy for commercial purposes for 15 years.A city inspector catches the Hispanics working on the job and the city stops the work.

A plastic splash guard, as @Colleen F. indicates, will definitely help in this case.

I now provide pre-cut thick plastic washable shelf liners and actually have a clause in my lease about damage to cabinets -- no nails, push pins, other sharp objects (I've had tenants hang pictures with pushpins on side kitchen cabinets, screwed in hooks to hang things) and that stains and damage to cabinetry will not be considered normal wear and tear.