How much do I trust Wikipedia? I don't.
Wikipedia does not - cannot - provide an authoritative source of reference.
Whilst there is little doubt in my mind that there is potentially much that could be or indeed is useful and relevant in probably most of the Wikipedia entries, there is also little doubt (from personal experience) that there is much that is seriously flawed - e.g., suffering from graffiti, vandalism, being opinion-based and irrational (as opposed to factual and rational), being biased, based on hearsay, apocryphal, or just plain wrong.
All this rubbish comes from anonymous authors, from registered Wikipedia authors, and from Wikipedia's so-called "professional" editors [Yeah, right.] alike. The latter in particular are very suspect IMHO, because some have been known to even lie about their "credentials" just so as to get into a position where they can influence the wording of specific areas of "history" or knowledge - all in the name of religio-political ideology, apparently. Or maybe they were paid to do it. Who knows?
Somewhat depressingly, I think, there seem to be a lot of people out there who don't like to see any version of the truth being promulgated except their own preferred bias or their own reality bubble or paradigm. In these cases, rational argument/debate is neither wanted/accepted nor tolerated, and often actively discouraged with prejudice. Critical thinking is a victim here.
From my experience, this seems to be especially so in areas relating to religio-political ideology, business management, science, and IT practice and theory - which all covers a potentially huge area of human information/knowledge.
This gives me some concern. For example, in IT in particular, where I have seen so much rubbish in IT-related areas that it makes me wonder sometimes whether the IT sector hasn't been cursed with attracting some of the most irrational, ignorant and narrowest minds on the planet - as well as some of the brightest.
In any event, my recommendation is to by all means use Wikipedia as a first point of reference - if you wish to do that (and it is very handy) - but not to leave it at that, and to always take what Wikipedia says with a pinch of salt until you can confirm what it says after having accessed authoritative sources.
I therefore avoid mentioning Wikipedia when I need to provide an authoritative reference to clients.
One of my personal favourites since childhood has been Encyclopaedia Britannica.