Has anybody continued to track every single thing they eat even after reaching their goal weight?

Yep, been tracking for 7 years. As @nossmf said, I eyeball a lot of food rather than weighing it now but I record everything. If my weight goes up or down unduly then I tighten up my logging and accurately record the calories. I use it as a tool to ensure I get my protein for my sport - left to my own devices I’d probably exist on carbs.

It doesn’t take me long at all; my OH is used to it but some family members / friends think it’s obsessive. But then they also think me exercising 4x a week for my sport is obsessive; that my desire to eat well to keep myself fit and active into old age is obsessive, and that preferring to eat home cooked food is obsessive.

Strange how they don’t think their alcohol intake is obsessive (I do drink - just not to excess and usually only 2 days a week); or that the fact they don’t get enough exercise and will find lots of excuses not to go out for a 20 minute walk is obsessive.

Different strokes for different folks!

Some do, some don't. I mostly have. For sure, I logged everything in the first months of maintenance, because I was still focused on making sure I had the right eating habits dialed in to stay at steady weight. I'm now in year 8 of maintenance, year 9 of calorie tracking.

Eventually, after the first year or so, I got more casual, and would skip logging days that I knew would be unreliable wild guesses, and just relied on the scale as a backstop. (Long experience tells me that what I do on repeat nearly every day has much more impact on my body weight than what I do on some truly rare single day, whether that's eating indulgently on a couple of holidays, or working out for 5 hours now and then.

Lately, I haven't been logging online at all (last couple/few months), but still write down what I ate on paper. (My habit when logging online has been to write on paper while cooking/prepping meals, then logging later.)

A couple of thoughts for you, besides the idea that different strategies are best for different people:

If you've been doing this for a month, you're potentially still at a point on the learning curve where the process is not yet totally easy and automatic. IF that's true, then you may find logging more sustainable after you've been doing it for a while.

Logging is a surprisingly subtle skill, plus there are parts of MFP that it takes time to learn to use efficiently. We need to get our recent/frequent foods populated with accurate entries, figure out when and how to best use the Recipes and Meals features and get those populated with useful stuff, etc. All of that makes the process easier.

I'd also observe that people sometimes hesitate to use a food scale because they expect that to be fussy and difficult, but once a person learns the tips, it's actually not only more accurate than eyeballing, but also quicker and easier than using cups/spoons. (Examples: Put the peanut butter jar on the scale, open. Zero the display. Take out a blob of peanut butter with the knife. See the negative number on the scale, log that many grams of peanut butter. Super quick, super easy. Also, build sandwiches (or whatever) right on the scale, zeroing between items, and noting the weights of each.)

For me, logging a normal day takes 5-10 minutes at most now. To me, that's a small price to pay for staying at a healthy weight for 8 years now, after around 30 previous years of overweight/obesity.

Finally, some people feel that logging forever can become dangerously obsessive, to the point that they don't want to eat things they can't log (like eating at non-chain restaurants or other people's homes), and they feel anxiety about precision. That's not good. Letting logging take control of our lives can be destructive. This is kind of a personality-driven issue. IMO, it's not the logging itself that matters, it's our feelings about it: Obsession, if it exists, is a thing happening inside our head, more than out in the world.

In that respect, I think we need to know ourselves. For me, calorie tracking feels like a fun, productive science fair project for grown-ups. If I forget to log something, or need to estimate, it's no big deal, a tiny drop in the ocean of life. I'm comfortable guessing (or skipping a meal/day) and going on with life. For me, I have less anxiety when I log, because I really, really want to stay at a healthy weight permanently - such a quality of life improvement! - and logging makes that easy and low stress. It would be different for some other people.

I want to underscore one thing: I feel very strongly that for weight management, the main focus is routine habits, the things we do day in and day out, our regular exercise routine and daily life activity level, the meals we eat in regular rotation, how we snack (or don't), etc. Whether logging forever is a good habit for a person or not, establishing the happy, practical new routine eating/activity habits is a key success factor.

Best wishes!