How long batteries last WILL depend on how you look after them and being sold the right ones in the first place. I can offer advice on the best way to look after your batteries and what is best for your requirements
We then get into should you have AGM or Gel batteries. It will depend on what your use is, for someone that uses a scooter or chair daily for long periods then GEL are the best option. For those who use it occasionally then AGM are perfect.
PLEASE NOTE: This is just a brief breakdown of batteries, should you need new batteries I will discuss with you all of the options and work out what is best for you, not what is best for me!