I've been extracting DMT for over a decade.
A lot of people have never had real pure DMT. In fact, even on the dmt-nexus forum, most people there do not even seem to know the difference between pure DMT and DMT mixed with NMT and other tryptamines.
Part of the reason for this ignorance is that for many years, until a few years ago, pretty much whatever Mimosa hostilis/tenuiflora bark you bought would contain some fairly pure DMT (high 90s percentage-wise and felt basically like synthetic DMT). However, starting maybe 3 years ago, I've noticed it is very hard to find Mimosa hostilis root bark (MHRB) with that same pure alkaloid profile. I was finding a lot of interesting and novel tryptamines, and had some of them verified by LCMS. Sometimes, the bark had no DMT at all from what I could tell, but usually it was something like 20-60% DMT.
Now, how can you tell whether you have pure DMT if you don't have a lab to test it? Some people would say Thin Layer Chromatography, but let me tell you, that is not very quantitative and the results are pretty variable with it in my experience.
But luckily there are some pretty simple ways.