Science fiction. Police procedurals. Fantasy. Technothriller. Historical.
If you don't take the time to do the research, your readers will be pissed. And they'll let you know about it, mainly by never buying your books and telling their friends not to buy your books because you don't know what you're talking about.
Yeah, even fantasy novels can get research wrong. Or get none at all. Horses, for instance, aren't four-legged cars that eat grass and go nonstop for hours on end.
But some fantasy writers will forget that.
I'm all for research. Research is good.
Do the research. Know your shit.
(And here's the big "But".)
Don't get lost in the research.
How do you get lost?
When you spend more time researching than writing your story.
You're writing a story.
Not a dissertation.
First and foremost.
Figure out what you need to know.
Then friggin' get back to writing your story.
Otherwise, you're wasting time.