Another change, after some reading and experimentation.  I installed partial dynamic publishing for archive posts this weekend.  I had to run at it twice.  It involves creating an .htaccess file and installing it on the server, and customizing some lines in it, creating a new directory on the server and changing some settings MT.  The first time I omitted some slashes in some path names in the .htaccess.   Once again, the MT documentation was right – just not clear.
The article about the benefits and drawbacks of dynamic publishing at Learning Movable Type may be out of date.  It warn that plugins often involve Perlscripts (and I still can’t use the word Perl.) which may not run in the dynamic environment.  One plugin generated a Smarty error – so I removed it.  The important ones, like Spamlookup, are written for php and run under Dynamic publishing.   I didn’t have a lot of plugins and the one that didn’t work has been superceded by newer MT tags, so I am not worried about it.
It makes rebuilding of the blog so much faster, which is convenient when I get into design changes, changing category names and all the other changes that show up on the published page.  Rebuilding all the individual entries took a couple of minutes, and it was just annoying.