Fitbit

Yeah my fitbit has got obese sitting on the sideboard.

Hi @rebecca1985 I would thoroughly recommend the use of a Fitbit. They are robust, stylish, cross platform, competitively priced, have excellent third party integration and a highly motivational.

I started with a Microsoft Band / Band 2, great devices but these had design flaws in the straps and have been discontinued. I have experienced three Fitbits and am currently using the Blaze. The fact it has lasted months with me suggests it is indestructible. Any of these types of devices can help you achieve both cardio and resistance based goals. After initial setup you can just let the automation assist you. I used my devices to track the length and speed of my walks, my calorie burn per day and to enter challenges with friends. If one is doing diet and exercise a Fitbit is a great addition and respects my phone and other choices without lock in.

It depends what you want it for and what motivates you and what exercise you do.
I have always been fit but when a fitness band (much much much cheaper that FitBit) was offered to me, I tried it out to measure how many steps I did a day and was happy that it was far greater than average. It wasn't super high but justified this to myself there aren't many steps involved with cycling and climbing but these both get my heart pumping.
Eighteen months later, I am still wearing a fitness band (I upgraded but still not to an expensive FitBit or Garmin or other well known brand). I have given myself the target of increasing my daily average over all time to 10K steps by the end of the year. Given how long I have been wearing it, this means I have to average more than 11K steps per day. This has resulted in some changes: on a plus note, I am leaving my office more often; on a less positive note, walking and running have taken from cycling so I don't get as much variety.
Some people import data from their fitness band to other apps to correlate other figures. I haven't yet come across one that imports fitness data and BG but I can see the value and know of some apps under development which incorporate fitness and health data. If you have Vitality health care, you can get cashback from exercise which can be proven through fitness bands.
I wear mine as a watch but if I am dressing up and wearing short sleeves, I go without because it looks ok from a techy perspective but far from glamorous.
Another thing to consider is how accurate it needs to be - some phone apps do a reasonable job of counting steps.
Finally, there is the option to get a reminder (vibration) that you have been sitting still for some time. This does nothing for me as I am usually on a phone call or engrossed in another activity which means it's not convenient to go for a walk.

So, back to my first sentence
- what do you want it for? Do you want it to track what you do or make you do more?
- what motivates you? Will you feel guilty because the numbers on your band are low or will you ignore them?
- what exercise do you do/want to do? If it involves steps, thats great but if it is cycling or rowing or swimming, you may need to look at specialist devices.

I've worn on for a year. I try and get in 8,000 steps/day on work days, maybe 10k on weekends. I'm pretty consistent, about 63k/week. I motivates me to get out and walk around at work instead of posting on this forum lol.