Here is what I have learned (the hard way.) When it comes to floor heating mats (and I will presume to some extent, perhaps the wire also) you may as well DIY. I took measurements, I paid extra to buy custom mats with a detailed floor plan at warmyourfloors.com and I asked the installer (who insisted he didn't need to) to watch the DVD with me before laying the mats. I had two mats, clearly labeled mat 1 and mat 2.

Then I made my mistake. I left to go pick up kids at school. I get a phone call (it's an hour round trip) telling me the mats are too long, they have too much left over, they can't make it work, and they are trying to explain why over the phone. I ask them to please wait, I will be back ASAP.

I get back to mats cut all over the floor and indeed excess at the end. Gee, maybe because you didn't follow the f&^%*ing floor plan and pull wire out at several junctures to fill, thus shortening the mat length? Why didn't I just lay it out myself and let them hook it up and take it from there? I knew I should have, then I decided, no I am being too controlling (maybe this remodel has been slightly, painstakingly researched) they can handle it!

Learn from my mistake. You DO NOT cut the mats until you are certain of your layout. The DVD showed us (I watched with him) how you flip and turn and finalize your layout before you cut. He didn't, obviously. What is really rich is he and the tile guy are ticked at ME because they are behind schedule now because they have been standing around scratching their heads over it.

Moral of the story: DIY! Ugh!