Most people don't realise there is a difference between trade quality paint and retail paint. As most DIY stores mainly stock retail paint, the majority of customers don't know there is such a thing as trade paint and assume it's the same thing but that the trade professional just gets a discount.
However, trade paint is of a much higher quality than general retail paint and provides greater coverage, requires fewer coats and gives a higher quality finish. This is due to the professional formulation process and a different pigmentation method. A professional decorator should not use DIY paint as the quality of finish can't be guaranteed.
Another misleading aspect of the DIY paint marketeers is that bathroom paint, kitchen paint or one coat paint don't deliver. These paints are aimed at the high street consumer. If you want a professional finish then you need a professional trade paint.
Please make sure you employ a professional painter using professional trade paint to give your home project a top quality finish.