Changing your lifestyle might take a little bit of work but it gets a lot easier when your monitor and track how you are doing. So let’s go over those things that are important to monitor.

Food Dairy
This one of the most useful things for anybody but it is especially beneficial to those who are just starting their transformation story. It is one of the best learning tools. For that reason I suggest it to 100% of people! You don’t know what you are ACTUALLY eating before you have measured it objectively.
Some methods that could be used:
1. Use pen and paper. Easy and cheap, but you’ll have to calculate macros and calories yourself.
2. Use PC and spreadsheet programs. For example Excel or Google sheets. Easier to calculate macros than with pen and paper.
3. Use online food diary apps like https://www.myfitnesspal.com/. There are hundreds, free and quality apps for PC, MAC, Android devices.
Activity Trackers
I consider those mainly motivational tools. For that purpose they work well (for some time at least). Also for people who want to walk more, the step counter could be useful. As for sleep tracker and other widgets - I don’t think they are accurate or useful enough for an average person to benefit from. But if you want a boost in motivation and don’t mind paying for it, go ahead!
Heart Rate Monitors
This is a very useful tool, if you know how to use it. Of course - the monitor has to be high quality, if it is a cheap version, then I would recommend you shouldn’t use it at all. What to do with your heart rate data? First off - getting to know how your heart rate acts in different situations, is a very good thing to know. For example - changes in resting heart rate can tell about nervous system disbalance. Significant changes in heart rate while sleeping can point to some kind of sleep disorder like sleep aponia. Then of course is the activity heart rate monitoring. This one comes in very handy when doing aerobic exercises and also monitor your aerobic improvement over time. Monitoring your heart rate returning to normal after exercise is a good way to analyze your recovery. There are many options which heart rate can be used. Is the heart rate monitor necessary? Not at all - I use to test many different kinds of wrist monitors but nowadays I prefer just taking my own pulse with my finger whenever I need it and I manage very well without fancy equipment.
Sleep Diary
This is useful for almost everybody to do at least once in the lifetime. Take a week or two and write down:
What time you went to bed
How fast did you fall asleep
How many times did you wake up and how long did it take to fall asleep again
At what time did you wake/get up
That night’s sleep quality from 1-10
Energy levels in the morning from 1-10
Any other things that might have affected sleep or how did sleep affect your day
You might find interesting things about your sleep and little things to improve it.
Training diary
This is a must-have tool for anyone who wants to systematically improve their physical performance. Either it is aerobic exercise length, heart rate, lifted weights or steps taken that day - writing them down is the only way to objectively monitor your performance. You might think you will, but you won’t remember those number 2-3 months from now.
I think you are getting my point. You could monitor basically anything. What YOU should focus on, are the things that are your challenges and goals. Nutrition, sleep, heart rate and recovery and physical activity are the most used and useful to almost everyone. Learn to monitor yourself systematically, not just for the sake of it. When you master it, you will reap the benefits.
Let's build a life that lasts.