It can be as simple a filtration system as one can make as long as it's effective. If you can filter twice, each time to about 20 microns, there really isn't much left that can cause a problem in a single season of flying. For most that could likely be extended out to a couple of seasons but an annual check of the condition of the fuel system should never be bypassed. If you can keep crud out of the tank, the tank filter can keep crud out of the carb.

At least for me the advantage of using a two filter system with one in the can and one in the tank is that it eliminates the break in the fuel lines for a third filter. That's one place gone that can't be a leak factor. There's no disadvantage to using a third filter for those that choose to do so, but it does add complexity, cost, and another location to worry about.

The turbine guys are another story. They have to be anal about their fuel systems.