Paint has been used for thousands of years and for three main purposes:
Paint material can vary widely depending on what type of surface you decide to paint.
Synthetic or Coach paint is the cheapest and by far the safest to use health wise and no buffing is required.
Two litres of Coach paint would paint a LWB Land Rover twice over.
Six litres of Cellulose or more depending on model and colour would be required to paint the same vehicle not counting thinners.
Cellulose is the easiest material to use, Prone to Blooming in cold weather, Requires buffing when dry.
Two Pack is really for professional use and is the most expensive, Requires a warmer environment and or a heated booth, Also requires buffing or polishing.
Acrylic is similar to cellulose in the method of application and close to the finish of a conventional two pack.
Stonechip sprayed on valances and sills of modern vehicles adds protection from stone damage, Stonechip is a flexable impact absorbing material available in various colours including clear.
Synthetic paint does not suffer from stone chips as much because it's already a softer material and absorbs the impact from stones.
Two Pack is the worst casualty from stone chips because of the very hard finish two pack represents therefore not absorbing stone chips particularly well.
Cellulose is soluble in it's own solvent even when dry, Two Pack, Synthetics and Acrylics are not.
Top Tip If brush painting, soak the floor or ground first to prevent dust and foreign matter from blowing around and landing on the surface. Mainly because coachpaint takes longer to dry and is more prone to attracting contaminants.