M58, I am left with 12 teeth in lower jaw and 8 in upper jaw. Should I get removable dentures or carry on like this? Pros and cons?

Missing teeth. Your teeth are important for your dental and general health. They help you chew, swallow, speak, and smile. The loss of a back tooth may cause your mouth to shift and your face to look older and effect your digestion. The good news is missing teeth can be replaced. Depending on your needs the options are: implants, fix bridges and removable partials. Rec. See your dentist today.
Get teeth. Always better to fill spaces. See about implants as well as removable partial dentures. See the specialist - the Prosthodontist - for all your options. Good luck.
Pros ; Cons. Pros: your will not spends any $$$ at this time to replace missing teeth. Cons: lack of proper support, especially in the posterior, will cause undue stress on your remaining dentition, resulting in premature tooth loss, shifting, and collapsed vertical dimension among the many other problems. In the end you will spend more money to replace more missing teeth. Protect your remaining teeth.
Implants. Your health and nutrition may be compromised without adequate teeth for chewing. Implants can restore your teeth to excellent comfort and function. Martial dentures are also an option with a lower cost but less comfort and function. Discuss all your options with a dentist.