I try to stick with what I know. I have a general interest/knowledge of vintage but I'm not an expert - when I write about vintage I always stick to the general ideas I am certain of(for example, the general principles of collecting vintage with regards to originality, what is collectible, what is not, very broad categories).
I never delve into the nitty gritty details of this watch/that part/this fake because I am not well versed outside of a few specific examples that I am intimately familiar with. I make an effort to stay within my own knowledge base, because I know that overreaching it can easily lead to trouble - or make you look like a know-it-all blowhard.
As I blog for a store, and my word readily returns to haunt me when clients take it as gospel and rely on me to make their decisions, so I make an effort to keep it trustworthy and just vague enough that they need to seek outside opinions to build their knowledge. I am very academic in my methods as well ("benefits of a classical education") and will retract or edit if new info comes to light, or if someone points out a mistake.
I always recommend doing your own research and learning from the pros, because that is what I do!
The more you learn, the less you really know. My favourite summary is this: