I use an app but I also have an excel sheet where I track everything very carefully every week or so.
Trust my excel sheet much much more.
Honestly for everyone I know this is how they do it. There is one guy who built his own app and his is perfect because he has solved for his specific bank accounts.
He knows every $ coming in and going out - its pretty impressive.
Writing it down yourself is still the best option for me at this point. I feel on top of things.