I think he's talking about modifications like changing the panel (going from steam gauges to glass), engine, etc. Assuming it's not E-LSA, of course.
If one builds it, the repairman certificate is worth a lot of money! One can repair stuff on one's own and sign off on it, such as fabric, replacing a windshield, and the annuals.
The standards aren't any more lax - best practices and AD's* still apply - but one can do them on one's own schedule! And major modifications will push one back to Phase I testing, of course, but that's part of the normal process and clearly defined.
Similarly, running an engine past TBO that is still sound (compression, etc.) is much easier, as one doesn't have to fuss with an A&P at annual time.
I write that knowing that I'll be on very good terms with our local A&P for help and assistance as well as a second, well trained set of eyes to keep me honest on airworthiness.
* While it's true that Experimentals can for the most part ignore AD's, it's not a good idea.