Looking for info on the difference between the 2. Can you substitute an sae for a mm and vice versa since the sizes are so close? Is there a preference for specific makes/models?

 

Not a good idea to use a metric wrench/ socket on a sae bolt/nut and vise versa, the sizes are off just enough to easily strip themail bolt/nut and make even more issues!

 

Agreed with Turbo. No garage tool collection is complete with wrenches and sockets in both SAE and metric.
I wish everything working on a car was metric, but it is what it is lol.

Now sometimes you can leverage that slight difference. So if bolt is having a problem with it's appropriate metric socket, I've pounded a SAE socket on that is a hair smaller and got the job done (but that is taking a gamble AND abusing the sockets).
But, I could not do with one or the other unless I knew I was never going to need the other.