Different people have different visual needs. If you are visually limited from performing your daily activities from cataracts, then you may be a candidate for cataract surgery. One does not have to wait until the cataract is "ripe", unless you choose to. Leaving a cataract in the eye is not dangerous except for rare situations. Cataracts in general do not harm the eye. In most cases, surgery can be postponed for as long as the patient desires or not done at all.
The only side-effect would be the blurred and progressively worsening vision due to the cataract. With time cataracts do increase in size and hardness, and if the cataract is very advanced, the surgery can be slightly more difficult to perform. However even in these situations the result is usually very good.
The surgical procedure that seeks to restore your vision involves removing the cloudy lens and replacing it with an artificial lens. Cataracts can be removed at any stage of their development, but again, the decision is yours alone. With modern microsurgical techniques, age or physical condition are seldom obstacles. The timing depends on how much your cataract limits your vision. When your vision becomes impaired enough to interfere with normal activities such as driving, reading or watching TV, then surgery may be advisable.