Which paint roller should I buy to paint plain smooth walls? Will roller paint drip? Is paint runner any good?

A medium pile 9 inch roller. Not a real cheap one. Wash it out thoroughly before use to get rid of loose fibres. Paint will spray. The thinner the paint and the faster you work it the more it will spray. Mask up. Invest in a roller pole.Which paint roller should I buy to paint plain smooth walls? Will roller paint drip? Is paint runner any good?
Spend some extra $ on your tools. Roller covers and brushes of better quality make a easier and better looking job , taking less time also. I use the trol products that are paint additives that lessen brush/roller marks and also thins it and makes it much easier to work with. I can use a $30 3'; brush to do everything from windows panes to trim, it just is so much easier to work with. I am not a painter just a handyman. The guys at the paint store(real paint contractors) told me about the brushes and additives. Yes to runner and use quality paint