You should give Bob a call. He is a “Pro on Toys” (Flir 1).
Spend your money wisely.
There is a big $$$ between T-4xx and T-6xx that you should spend on your brain, rather than the camera (if you don’t have unlimited resources). In time as you build your business you will come to the point you need better equipment for what you are trying to accomplish.
You can ask Jim Sefferin, he doesn’t use just one camera for all applications.
As a Building Science Thermographer, you will need more camera. But as a Home Inspector, because of the Distance, Delta T, Emissivity you deal with, a T-4xx is a good match.
I have a T-620, T-400, and BX320. I only use the T-620 when I have the need for the job (like commissioning a power plant). I use an upgraded T-400 with wide-angle to do most Building Inspection (and places I don’t want to take a $30k camera) , and the BX320 for all other activities (and as a backup camera). Talk to someone who has worked a job with $1k mobilization cost and their camera didn’t turn on when they got there! I always have a spare.
Most of the Veteran Thermographers here only had one choice of cameras when we started (BCAM non-SD). Your choice is huge. Choose wisely.
Note: By the time you “Know” how to use a really high end camera, you will have burned up at least one camera in the process and newer, cheaper, better cameras will become available. I always buy a camera one generation behind the latest and greatest and have saved $$,$$$.
($10k for MSX is not a good investment.)