I recommend a primer if you need your make-up to last ultimately for an important day or event. It will help your make-up to stay in place all day and is especially ideal in warmer climates.
Primer is best applied in a thin layer using a foundation style brush to blend evenly into the skin enabling foundation to glide on evenly and smoothly for a long lasting flawless finish. Use a pea sized amount, concentrating mostly on the t-zone area.
Primers can be great for minimising open pores and fine lines, reducing oil and brightening the appearance of the skin helping greatly to prepare your skin perfectly for make-up.
Choose your primer based on your skin and what you want to get out of a primer i.e. If you have dry skin choose a hydrating primer to brighten your skin.
My favourite primers I recommend are below:
Dermalogica Age smart skin perfect primer (illuminates and brightens SPF 30)
Daniel Sandler Retexturising primer (smoothes pores and lines, SPF 20)