I think it has been firmly established that the scale you step on every morning is a lying piece of crap that can’t be trusted. But if you don’t have specific measurable goals, how will you ever know if you have arrived at the place you want to be?
Having a goal weight isn’t a bad idea, though that is a number that is fairly easily manipulated and somewhat meaningless anyways. I’m personally a fan of bodyfat percentage as a reasonable metric, but it is something that is essentially impossible to measure with complete accuracy in a living breathing human. If you want to go the autopsy route, be my guest, but it’s essentially a one time thing and any further body composition changes will come in the form of decomposition.
BodPod is a not terrible method of measuring body composition, and probably the best compromise between accuracy, speed, repeatability, cost, and all that other stuff. If you are in a major centre, you probably won’t have too hard of a time finding one. If you’re not, good luck. DEXA is great, but it’s generally significantly more expensive than BodPod, and harder yet to find. Underwater weighing seems to have fallen out of favour in recent years, so again, good luck finding this as an option. BIA systems are very prone to error and are only consistent at being pretty crap from what I understand.
My personal choice of tracking measures are circumference measurements and skinfolds. For circumference measurements, both biceps, both thighs, hips, chest, and 2” above, 2” below, and at the navel is a good set of things to track. These will allow you to see where you are gaining or losing, and get a pretty good feel for if you are losing much muscle, at least once you get down to normal levels of leanness and below.
Skinfolds can be taken in a number of different ways, and you can google for them if you are really interested, but be aware that most of the formulas and standards are only really accurate on the aggregate for average populations. So if you do use skinfolds as a measurement, be aware that if you are using (for example) the Jackson-Pollack 3-point formula, and it tells you your body fat percentage is 10.38%, you can’t put too much faith in that exact number. Where skinfolds excel however, is in showing you progress over time. If your scale weight isn’t moving, and your circumference measurements are staying about the same, but your skinfolds are going down, you are probably losing a bit of fat and gaining a bit of muscle.
The combination of weight, circumference, and skinfolds allows you to get a better handle on if you are actually making progress or not. If any one of them is steadily decreasing, you are probably still doing alright and moving towards your goals.
If you find that all three measures have stalled out and aren’t changing for at least a couple of weeks, you can reasonably assume that you have stopped making real progress, and need to make some minor changes. Either add more activity, or decrease your calorie intake. An additional deficit of 200 cal/day should be more than enough to get fat loss moving again, though this will depend a lot on you and your levels of leanness. And all sorts of things that are beyond the scope of this post.
That was a good set of objective measures that you can track to keep an eye on your progress. If you want a really good subjective measure or goal, going by clothing size is a winner for a lot of people. Fitting into an old favorite pair of jeans or a dress is something you can test quite easily, and also something that many people would consider a pretty significant accomplishment. Though depending on how many squats you are doing, you might just blow that pair of jeans out at the thighs. It’s a tough problem to have, and a lot better than having to stop half way up a flight of stairs.