I'm not a pro but I can share with you what a pro taught me when he did my house. First, if you're painting other than a white, you'll get uneven areas showing more due to variances in your texture (some will suck more paint). If it's any color other than white it is usually primer plus two color coats needed. If you are paint a deeper color, try tinting your primer 50% of the finish color to help with density. The exception is the red palette, add black to primer to make it med to dark gray depending on your red. If you tint the primer with red, you'll get pink and it won't help get the deep color desired. Deep blues are also a hard color to get even and dense. Deep colors may require 3-4 coats. White-based, lighter colors can be done in 1 to 2. Just thought of this: what nap are you using if rolling? The pro guys use one step heavier than most homeowners to get more paint on and get done quicker, ex: a 1/2 inch instead of 3/8 on smooth/med surfaces. Hope this helps.
