You do not have to work that out yourself. Mention anything that feels off, such as toothache, bleeding gums, a tooth that has changed or sensitivity, even if you booked to talk about colour. The dentist checks your mouth first and tells you what they find.
Bleeding gums can be a sign of gum disease, as Teeth cleaning guide explains. If that is your worry, our gum disease treatment page shows how we approach it. Say when the symptom happens and whether it is changing, rather than describing it only as something that spoils your smile.
Afterwards, ask for the findings to be explained in two parts: what needs care for your health, and what is an optional change to how your teeth look. A veneer, for instance, does not treat decay or fix your bite. Having each part named separately, with its own cost, makes the decision clearer. Bring the names of your medicines and any earlier dental work, since the Guide to dental treatment describes these as part of a check.