Primer can be very helpful when painting a room. There are 3 types of primers — drywall, deep based and problem solving.
Premier drywall primers are useful if the walls have an irregular surface or you are painting natural drywall or wood panelling. They can also be used to spot prime any areas where you have just repaired or filled in cracks or holes. This will help prevent the sheen from looking different on the surface.
Premier deep base primer should be used to lessen the number of coats required for bright, rich colours.
Finally, if you have problem areas such as stains, odour or mould, you should clean thoroughly and use a Premier problem solving primer.