When I decided I wanted paneled doors instead of my old flat ones, I came up with an innovative approach. Instead of buying new doors, I saved money by adding panels and some paint to my existing doors.
Why not just replace the doors?
My old home's door height was unusual: 78.5 inches. Custom doors would have been too expensive.
And by adding panels to my old doors instead of replacing them, I avoided the hassle and risk of measuring for new doors -- a process that requires precise measurements of the location of the hinge, knob, and lock for each door. Had I made a mistake in any of these measurements, the new door would not have fit the existing doorjamb.
How did I add panels to the old doors?
I built my new door panels from window casing. Here are the steps I followed:
1. Using a large ruler, I drew two large rectangles on one of my doors to represent the panels I wished to build. I then measured the width and length of each side of the rectangle. To make the project symmetrical, the top and bottom panels on the door had to be identical.
2. I bought window casing at a lumber store rather than a home improvement store, as this reduced the cost. This also meant that I could buy the window casing in bulk and bring it home in my SUV, thereby avoiding delivery charges.
3. Based on my measurements, I built one panel from window casing. Like a picture frame, the panel was made of two identical width pieces and two identical length pieces. I had to try a few times before I was able to get the exact 45-degree angles I wanted, so the mitered edges would meet perfectly and form a rectangular frame. Each time I adjusted my saw, I made a note of the setting. Thus, once the panel was perfect, I knew exactly what saw setting I used.
4. I then used the four panel sections as yardsticks. In other words, all future panels were easy to cut. I simply placed each yardstick piece beside a fresh piece of window casing, marked with a pencil where I should cut, and proceeded with a saw.
5. Finally, I glued the panels onto the doors and painted them in eggshell-white latex paint.
How much money did I save?
The cost of each door makeover was $28, which included adding panels to both the front and back of the door and painting each door. If I do this project with closet doors, I'll save money by not building panels on the back of the doors.
A new door, on the other hand, would have cost from $50 to over $100, depending on the style and quality. Add to this the cost of custom-fitting the door for hinges and a knob as well as delivery and haul-away costs, and the price of brand-new doors goes up even higher. In fact, the project cost me $255 (for nine doors) instead of an estimated $675, giving me a 62 percent savings.
Lessons learned 
During this project I learned a few important tips:
1. Don't start by cutting your window casing. Instead, practice on cheap 2-by-4 lumber until you are comfortable cutting 45-degree angles with your saw.
2. On the back of your panel yardsticks, note whether the saw needs to be set to the right (R) or to the left (L). This will prevent you from getting confused.
3. Be sure to take the doors off the hinges and set them on the floor before you glue the panels on. Otherwise, the panels will be pulled down by gravity before the glue sets.
