I'm addicted to mods...

I think the TT manufacturers do a pretty good job of covering the basics, but they are naturally going to leave out options/mods that won't provide much in the way of competitive advantage or ROI. I used to be in Product Management in a different industry and that was why we also offered after-sale options.

We're in year two of having our TT and we are mostly in the fine-tuning stage of things (e.g. 1 extra Command hook under the bathroom sink, etc). But things we did in the first year, like the Maxxair vent covers were essential to us getting the most out of our new camping buddy.