Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Seek emergency eye care rather than waiting for a standard appointment.
Contact the surgical team promptly for increasing redness, pain, light sensitivity, discharge, or a clear decline in vision after surgery.
New flashes, a sudden increase in floaters, or a curtain-like shadow need urgent assessment because they can be symptoms of a retinal tear or detachment.
A cataract that is not yet affecting daily life can usually be followed during routine eye appointments.
The eye care professional will recommend the timing based on vision, cataract progression, diabetes, glaucoma risk, and other findings.
Arrange an earlier assessment if gradual blur, glare, or night-driving difficulty begins to interfere with normal activities.
Sudden severe eye pain or sudden major vision loss is not routine cataract progression.
The article also says
After surgery, attend all scheduled visits even if the eye feels comfortable.
These checks allow the team to monitor healing, eye pressure, inflammation, and the position of the artificial lens.
Vision may fluctuate during early healing, and a final glasses prescription is usually considered after the eye has stabilized.
Every sign above is quoted from the sofidex article on Cataract - adult. If you are not sure, err upward — it is always reasonable to be checked.