Where do you go to confirm if the tool you have is correct enough for your planned use?

I would like suggestions on the tool map you use before buying a new tip or accessory when deciding to do something (cut clean sharpen carve) in a specific type of material (wood plastic steel iron)...

I own a dremel 4000, as or reference.

I've been doing a lot of testing on my own for which Dremel bit types and materials "work" for my own needs, but have always been wondering if I'm not using the best "tool" (bit) for the job. For example, I was cutting my own brass flywheel guide for a Rayven cage the other day and I knew to use the reinforced "metal" cutting wheel, which worked just great for cutting the flywheel slots, but when it came time to smooth out the cuts I had made, I wasn't sure what to use. I started by using the silicon carbide grinding bit that came with my starter kit (looks like this: https://www.dremel.com/en_US/products/-/show-product/accessories/84922-3-16-silicon-carbide-grinding-stones ) but the brass ate away the bit material very fast. Next I tried using an aluminum oxide grinding stone (like this: https://www.dremel.com/en_US/products/-/show-product/accessories/8175-aluminum-oxide-grinding-stone ) and had less trouble with the bit wearing down, but it took a lot longer to make progress and seemed to produce much more heat in the meantime. I eventually got the job done, but couldn't help but wonder if I was simply using the wrong bits for the job!

All this said, I know that the community extensively uses rotary tools for nigh infinite different purposes in this hobby, so I was hoping that those of you with much more experience might weigh in on what their favorite bits are for various functions/jobs. As far as I can tell by using the almighty search function, I don't believe this topic has been extensively explored on this subreddit before! Honestly I'm not sure why I haven't seen a video about this from any of the bigger youtube personalities yet... hint hint ;)

I got a dremel with about a dozen attachments in an unlabeled box at an estate sale. Is there a way to tell what material a given attachment is intended for, short of trying it out and seeing if it breaks? Specifically, I have a project where I want to cut or grind some metal, and I can't tell whether any of the attachments I have can handle metal, or if it'll just ruin them.