1.

Only use an interior shop with an on-airport facility.  You want to be able to fly in, park - see the work being done on your interior at any time.  No off-airport shops unless you've had excellent referrals from people you know who've had personal business with the shop.

2.

Have a written contract that outlines in detail work to be done.  Divide contract by areas, i.e. Instrument Panel, Seats, Side Panel, Headliner, Carpet, Seat Belts, Accessories, i.e. Writing Tables, Storage Drawers, Refreshment Center, Potty, Cockpit Dividers, Doors, Stairs, Placards.  Be very detailed and very specific.  Example:  Address Seat Repairs/Painting, new Foam, Stitching, etc.  Another example:  Writing Table - old wood reworked - how?  New wood?  New Laminate?  Just the top or other parts, etc.  Remember paper and ink are inexpensive.  Have a detailed written contract.

Photos of other aircraft, brochures, and ads - are great.  Use them as an attachment to a contract.   Both shop and owner can initial.  However, photos alone without a detailed written contract is asking for trouble.

3.

Require a detailed materials list.  It must be specific.  How many yards of leathers, fabrics, carpet.  Cost per yard.  Minimum quantities required by suppliers.  Amount and cost of laminates, belts, etc.  Cost of hardware and new placards.  Cost for outside vendor work such as plating and polishing.  Get copies of estimates/quotes from outside vendors.  The contract should state that all materials not used are the customer's property.  Example:  Perhaps a certain laminate is only available in a large sheet.  After the job is over - rent a truck and get all of your materials.  You should know in advance how much to expect upon completion.

4A.

Deposits:  Your initial deposit should only be for materials.  No labor until the project is ready to be started, and that means all materials are present and accounted for.  Commencing a job with a few items on back order is the first step to trouble.  Don't gamble.  If necessary let your project be rescheduled until all materials are in.  You'll be surprised how aggressive a shop will be to its suppliers if they're causing a job to be rescheduled.

Remember, if your project is begun and then put on hold while materials are on back order, your disassembled aircraft suffers.  It's likely in a hangar corner and somewhat apart.  It cannot be run-up.  Electrical phantoms move in.  Your accurate DME and segmented digit displays go dark.  The interior shop will not be paying for these repairs.  By taking time, and insisting on a detailed list of materials, quantity and costs (Item 3) there should be no "extra" needed materials during the project.

4B.

Similar to construction, place the full amount of labor in an escrow account and authorize pay-outs at agreed to stages, providing the shop has satisfactorily completed work to date.  Very simple: you live up to your part of the bargain and have a structure that requires both aircraft owner and shop to perform.

5.

Plan to show up at the on-airport shop unannounced from time to time.  Ask the shop to advise immediately of any problems.  Plan to visit the project before/after a particularly critical aspect of the project.

6.

When the aircraft is ready, schedule an adequate period of time to carefully inspect every item in the contract.  Perhaps all day.  Just don't go pick it up.  Call and have the battery charged.  Schedule and conduct a comprehensive pre flight inspection and a test flight.  Before flying check all interior lights, vents, seats, belts, equipment and accessories.  Remember A & P's have not been working on this aircraft.

Carefully inspect critical areas like emergency escape doors and cabin doors.  Especially in a pressurized aircraft.  Confirm adequate on board oxygen and masks for all test flight crew.  Prior to passing 10,000 feet, make sure oxygen supply is working.  A full powered run-up is advised before takeoff to confirm turbo and waste gates are working.

A pilot with knowledge of the pressurization system should carefully monitor system operation as the aircraft is taken to altitude.  A "properly qualified" passenger should move to Aft Cabin to check for leaks and wind noise that might result from improperly installed components.  Crew should check heater/defroster and air conditioning operations.

7.

Review and address any discrepancies associated directly with the interior project.

8.

Confirm proper airframe logbook entry, burn test documentation and any necessary weight and balance changes.  No original logbooks should have ever been in the shop's possession.  If necessary, a copy of the aircraft's last weight and balance and last airframe annual entry can be supplied.

9.

Properly store extra materials.  Protect from sunlight, dust, and moisture.

10.

Properly care for new interior.  Frequently treat leather, dust and vacuum and clean wood laminates.  Do not heavily load up and cause seat pouches to sag.