Do you collect data in whatever way seems most natural for your current project?
I rarely have control over this (like, I can't remember the last time that happened), but I'd say yes. The beauty of writing scripts to process and wrangle your data, is that you don't have to redo that work every time. You certainly want to have your data well-structured, but the best method is decidedly scenario-dependent.
As for the where, I think this also depends. If I had to type a bunch of numbers in, I'd probably use Google Sheets, but I don't know much (read: anything) about RedCap. Another option, if you're entering text that repeats (categories, etc) is using something like Google Forms, where you can restrict the number of choices. That way you can avoid things like spelling mistakes, which can just make processing your data later a bit more annoying, and skip some of the pain of manual entry.
Here's a post on using Google forms for data collection (and analysis, but obviously I wouldn't recommend that
)
I'm sure there are lots of other options, just speaking to the limited number of tools I know!