Warhammer, and 40k in my case, is inherently all about "What if I add this or that unit into my army?" This triggers an entire workflow:
1) Theoretical thought about usage and tactics concerning the unit to add.
2) Collect the models required for the unit based on theoreticals of previous step.
3) Assemble the models.
4) Paint the models.
5) Play long game(s) with them, and ask yourself the question "What if I add this or that unit into my army?"
This gets tedious over time with any army. So what do most players do? Decide to collect another army, of course! And the cycle repeats itself.
After time, this in itself gets tedious/expensive/time absorbing, causing players (well actually, I'm talking mostly about myself) to quit the hobby and start spending time and money in other pursuits.
After a hiatus of over two and a half years, I'm back into the hobby!
What a better way to reboot than painting a Chaos Marine from the Dark Vengeance set.
This guy was already undercoated with black paint and had already received a zenital highlight using an airbrush several years ago. He's spent his time gathering dust (as death guard tend to do) but yesterday I decided enough is enough.
Continuing on with my last three Panzer IVs. Yesterday I airbrushed the camo onto them.
After a bit of a fight with my airbrush (which, as usual, came down to a proper cleaning of the airbrush) I got the paint down.