What are some of the things that cataract patient should look out for?

Vision decreasing. Cataracts (a white lens change): most often due to/made worse by (most common first): aging, genetics predisposition, excessive sun exposure, smoking, diabetes, steroid medication, previous trauma, inflammation, infection in the eye causing inflammation; previous intraocular eye surgery; other genetic conditions; can be congenital; Symptoms: glare especially at night; cloudy vision, decreased VA.
Problems seeing. Really nothing to look out for. If the cataract (cloudy lens) causes changes in your vision that affect your normal activities, then cataract surgery may be considered or indicated.
Glare. Cataracts can cause glare symptoms or blurry vision despite glasses. Night time driving can be adversely affected and should be carefully monitored.
Vision changes. Cataracts are typically not significant until they cause visual symptoms not correctable with glasses. These things include slow progressive decline of visual sharpness, haze, glare/haloes, or difficulty doing normal activities such as night driving, reading, watching tv, etc.