It is important to consider whether one is going to be by oneself or if a partner is going to help with daily tasks, including loading and unloading a mobility aid.
If you can no longer walk or stand, a mobility scooter is probably not the right choice for you; you will probably require a power-wheelchair. If you can still walk a short distance, than you almost certainly do not want to sit in a wheelchair, and an electric mobility scooter may be in your future. You will have a choice of 3 and 4-wheeled scooters. If you are quite frail, the latter (4-wheeled scooter) may be the better choice. 4-wheeled scooters generally are considered more stable in curves, but this depends on track width. A narrow 4-wheeler can tip over more easily than a wide 3-wheeler. The decisive drawbacks of 4-wheeled scooter are the significantly higher weight and the relatively wide turning radius. These scooters often require custom vehicles and/or lifting devices for transportation.
3-wheeled electric mobility scooters are the choice for people who’s feet don’t want to play along but who are otherwise in fairly good shape. Walking disabilities are often accompanied by trouble lifting, and thus, low weight of any mobility aid is of paramount importance.
There is a wide selection of 3-wheeled mobility scooters, and more than a few advertise as being the "lightest", even though they are anything but. One popular advertising ploy is to minimize, obfuscate, downplay, disregard or omit entirely the rather substantial battery weight.
That is why you should examine the manufacture’s / dealer’s weight specifications closely, and ask when something is unclear. It is also a good idea to try lifting the scooter, such as in and out of a car. If you have to make your purchase decision from home, you might try simulating the scooter weight by placing a similar load on a chair and lifting it.