I own 2 miter boxes. They are cool tools to have around, but I’ll be honest I rarely use them. In fact I have deterred several folks from getting one when asked. It’s not that they are not useful, but like any fixed tool their function is limited by the capacity of the tool. The truth is that with some basic control of a hand saw you are able to make cuts just as precise without the miter box. The way I see it is that regardless of how I do the sawing, I’m probably going to clean up the saw marks with a few plane passes anyway so why lug out the miter box when I can just use a bench hook and back saw. I keep my miter boxes around for the times when I need to make a lot of the same angled cut, but most of the time it collects dust.
This video shows one of many techniques to precise sawing and I find it particularly useful on wide or thick stock where a little deviation will translate to a very errant cut.
What is your preferred technique for precise saw cuts? Do you own a miter box and if so, how much do you use it?