How to check moisture content and expansion gaps before installing LVP flooring?

When renovating an old house with LVP, many problems don't start during installation, but because pre-installation checks weren't done. On a previous project, the floor buckled two weeks after installation; when we pulled it up, we found the subfloor moisture content was too high and the expansion gaps along the walls were too small. My process is to first use a moisture meter to test the…