The title is really a question with a simple answer, yes! When fellow customizers post on social media about issues they have with paint of any sort, someone (if not me) will ask them, "Did you prime the figure?" 9.5 out of 10 times, the answer is "No."
What a lot of new customizers don't realize is there really is nothing but advantages to using primer. For starters, even if you are washing the mold release off of your base figure, the smoothness of the plastic prevents paint from properly sticking to the surface. Primer prevents more watered down paint from bubbling up and being wicked away from the area it was applied.
To Prime or Not to Prime
Next, primer allows the painter to start with sort of a blank canvas. This is probably the biggest advantage to priming. Not only does it allow you to easily paint difficult colors such as white and yellow with smoothness, but also creates a perfect balance on paint. For example, I saw a custom the other day where someone converted a new Captain Marvel (Carol Danvers) into a 90s Jim Lee Rogue. The painted on yellow was noticeably brighter and more orange color over the red section of the torso and darker yellow over the dark blue sections. This really takes away from what could have been a great custom.
That Is The Question
Not sold on primer yet? How about I tell you it saves you time and money? Sure a decent can of primer can cost you around $7-$10 but you will save that money in time to finish a figure and allow you to do it while using less paint. Instead of having to apply many thin coats of paint, a primed base figure really only needs 2-3 coats for complete coverage. Not only does this save you paint, time (verses having to apply 5 or more coats for decent coverage) but it also lowers the risk of joint rub since you are applying less layers. Another way to save money on paint is various colors of primer can be used with paint to create different effects. In the two attached pictures, each figure was painted with the same colors of paint, I just used different primer color.
So what brand of primer should you buy? Most paint companies suggest that you buy their primers with the paint and that should be the case most times. The reason for that is the best results that the paint manufacture got with their paint is when they were testing it with their primer. Now I am not saying you are going to get horrible results when you use Krylon primer with Vallejo paint but Vallejo did all of their quality testing with their primer. Personally I use Duplicolor Vinyl and Fabric Spray as it creates a great thin layer that takes paint very well and it is more durable than previous primers that I have used. I find it at Autozone, and depending on the store, they have a wide selection of colors to use. Now you have the basics of primer and the advantages using it has in the process of making a quality custom. Before I leave, I just want to say make sure that you spray in a well ventilated area and read the instructions of the can. Good luck customizer!