In preparation for replacing several entry doors I've been reading some different step-by-step installation guides and I'd like to get some opinions on the best methods. I also watched the TOH video of Tom Silva on installing a prehung entry door.

I have not yet torn out the old doors and so I'm not sure what I'll find, but my house went through a major remodel in the mid-80s so I believe I'll find circa 1980 materials an methods (hoping for no surprises).

Most of the differences I have noticed between the TOH video, the manufacturer's instructions, and other DIY websites relate to the prep of the door cavity. Some sites say to use "z" flashing above the door, some say to use an adhesive membrane at the threshold, etc.

What do you experts recommend and just for reference I usually like to go above and beyond minimum code requirements. I like to have it done right once and hopefully I never have to do the same job twice....

Thanks for the insights!