On top of all the other performance improving mods I've installed lately this one is the icing on the cake.

I've been testing it out with one of my larger households: eight sims living in a big complex house with lots of tight spaces, small rooms and narrow passage ways, and they are all getting about far better than they did before, No more cancelled actions because somebody got in the way, and far less routing tantrums.

It seems to be improving matters elsewhere in town too: I played for several sim days and didn't get one Nraas 'unrouteable sim' message. Normally I would have had dozens by now..

I was going to say 'game changer' but somebody already did, so I'll just agree whole heartedly. Well done, and thank you for a great mod.

Oh my, thank you Really appreciated
The original reason for me, to make this mod, was pretty similiar to your problem: got a house, so big, complex and with many tight spaces, that the routing of my beloved simsies got weird. This frustrated me so hard, that I didn't change my house, but made this mod instead Probably the origin story of many inventions :D

Thank you so much for making thias and for sharing it with us!! ^^

HI, just to clarify -- do I need every expansion pack for this mod? Or does it just edit what it does to each expansion pack, and is base game compatible?

No you don't need every expansion pack for this mod to work. In the download are many files, each containing the name of the expansion it requires. If you have no expansions, install only the base game file. If you have the world adventures expansion and the pets expansion, install the files that have the expansion names in the filename, plus the basegame file. Always just install the files of the expansions you have.
Hope this helps.
Happy simming