I have Mint, but use it more for looking at my net worth quickly.
For tracking actual expenses, I use an excel spreadsheet. I would say that I was like you, I didn't spend lavishly, and there was always money left over at the end of the month. I wasn't really paying attention to Mint, since I didn't devote the time to categorize things correctly, and found it frustrating that I would have a gas expense and a fast food expense get categorized as gas when I purchased them at the gas station (gotta love QT). I would have to manually adjust them, and found that annoying.
When I decided to start a spreadsheet, I had the control over categories. I set it up, and was happy with it, then was curious at previous spending, and back filled it for a year by looking at previous credit card statements. A few months after that, I back filled 2016 expenses as well. They aren't completely accurate as they are missing any cash, but it's better than nothing.
The effect this had on me was that I realized I was paying too much for home and auto insurance. I switched both. I also realized that while prepaying my mortgage gave me warm fuzzies, I was better off increasing my 401k to the max as well as my HSA. This in turn led me to calculate out how much taxes were being withheld, and to adjust those so that I should be within $20 when I file my taxes in 2019.
I actually look forward to filling out my spreadsheet when I have an expense now. I know how much I have budgeted to each category, and can see when I am getting close or have gone over. For me my budget is hard and fast, it is a guideline that I try to keep to what I have told myself. It is mainly to be mindful of where I am.
I have all of my bank/credit card apps on my phone, so I can quickly access a previous days spend. If a purchase at the grocery store has food and cleaning supplies, I take a photo of the receipt so that I can break it out on my spreadsheet accordingly.
I find that keeping track of spending has made me enjoy cooking at home more, and then when we do go out to eat, it is much more appreciated.