Regarding the first point, things are clear: buy paint that you can afford. House features are, and they are very important in that house masonry requires a completely different choice than one timber, for example.
Another categorization divides these substances in paints Support and decorative paints . The former does not remove them itself out but, on the contrary, their role is to `sprijini` somehow shadow, decorative performance of other objects (furniture, structural elements, etc.). Decorative paints were just supporting role as first an object or area by using their colors and textures.
Some tips and more practical now. If you have house south oriented exclusively buy paint to withstand UV rays. Choose only paint ready, refusing the idea to add pigments in a white paint. Even with car colorimetric differences may appear, where paint was prepared in two shifts.
Otherwise, everything you need is put on the box, you just need to be very scrupulous compliance those indications!