How do I view and track expenses by category and by credit card/account?
My wife and I use different credit cards for spending, but I am trying to see how much each of us spends on different categories? As an example, if I have “clothes” as a category, but categorize each transaction as such, they get grouped together on the spending trends tab. Do I need to setup two different categories such as “my clothes” and “her clothes”?
This is a perfect use case for tags. You would use one category of Clothes, but then tag each Clothes expenditure with either your name or her name. Then, you could run a report that included everything with in the Clothes category with either your name or her name as the tage. For more on tags, see here. For running reports, you could either use the Tags Report or the Transaction Tracker.
Tags are a critical part of my Tiller set-up. I use them for precisely the case you describe (to see how much my teenagers are spending on various things 
) or, for example, to track all of the expenses related to a vacation across different categories so that I can easily see the total cost of the vacation.
If you’re looking to see this information on the Spending Trends tab, then it seems the best way to do it would be to use two different Categories under the same Group. Tags would be useful as recommended by dmetiller, but you can’t breakdown by Tag on the Spending Trends tab which is why I ask where you want to be able to see this information.
Perfect, thank you for the info. First time user here so still getting familiar with the features!