What is a good expense tracking routine that only takes a few minutes a week?

Pick a consistent cadence rather than tracking every purchase in real time. A five-minute weekly review works for most people: open your bank and card apps, scan the week's transactions, and sort them into your categories. Flag anything surprising and adjust the rest of the month if a category is running hot. Once a month, do a slightly deeper 15-minute review to catch subscription creep and reconcile against your plan. If manual entry feels like a chore, use an app that auto-imports and auto-categorizes transactions so your job is just to correct mistakes. The point is awareness, not perfection. Even loose tracking beats none because it closes the gap between what you think you spend and what you actually spend.