It also was a nice perspective to have in mind for me. Calories in, calories out means it doesn't really matter what I do today, it's what I do each day that matters.
For home-cooked I would do rough estimation based on weight and some quick web searches for calorie content of the ingredients.
After a short while I got a pretty decent hang of where the calories were, so could focus more on those. I had a small kitchen weight for the "heavy hitters", for the rest I just estimated based on listed weight and how much I used (~1/3 of package fex).
In the beginning I did weigh slices of bread and so on, and quickly built up a good overview over how many calories there were in such recurring items. Except for oils, butter and similar I wouldn't be super-accurate.
But having a fairly good idea of how many calories was in my food really helped me plan portion sizes and compositions to roughly match the deficit I wanted, as determined by a web page estimating my calorie requirement[1].
Like I said, focusing purely on calories in, calories out, rather than say "yes foods" and "no foods", made it a lot easier for me as I could eat what I wanted, just perhaps not as much.
For example, I quickly found out that my weekend favorite of steak with french fries and bearnaise was way over target. However, I found that if I ensured my steak was no more than 250g, swapped french fries for quality green peas and reduced the butter in the sauce by half, the calories were around my target value. So I could still enjoy my weekend treat.
One potential issue was to feel full while reducing portion sizes. For that I leaned on some studies I read about which seemed to suggest high protein and high fiber. So I tried to have at least 20% of my calories in proteins, and also have as much fiber as possible. My breakfast bread is 90+% whole grain, my pasta is whole grain, I swapped out iceberg lettuce for romain lettuce (which has much more fiber) etc.
Based on this I had a almost entirely linear decrease in weight over a year, without feeling like I was on a diet. In the end I lost 30kg.
[1]: https://nhi.no/skjema-og-kalkulatorer/kalkulatorer/diverse/b...
Some types of meals are easier than others, though - e.g. if you make a large pot of "non-uniform" soup for the whole family for multiple meals, then it's going to be an estimate. It's socially inappropriate to do it at some situations (e.g. if you're visiting your grandma who's providing a meal), but on most days you should be able to track how much calories you got on that single day.
Some restaurants will provide numbers for their dishes, some won't. For takeaway/home orders weighing gives a good estimate - if you don't have the numbers for some kebab or sushi or pizza, then you can assume that it's going to be the same per unit of weight as someone else's similar product, what matters is how much of double cheese pepperoni pizza you eat, not the particular pizza maker.