Plus we have a Racor (Parker) dedicated low amperage/volume polisher with it's own filter.

The main advantage to use is that we can leave valve serving one filter. If you had a problem with gunk or water because of bad fuel, boiterous sailing stirring-up crude/water, etc -- then you can simply switch filters and hopefully move-on. (We have port and starboard fuel tanks, also -- so if you have the fuel left in the other tank, you're doubly protected.)

I think that the new fiters have aluminum heat shields below the drains (which makes draining them more cumbersome. I believe it's a waste -- but that's the current "standard" for new filter bodies. Our dedicated filter has one of these for the polisher -- the older double filter arrangement doesn't.

It also helps if you have a vacume guage. That's helpful as a relative measure of the filter's cleanliness. You can get a filter packed, but have little visual signs if you use them for muliple seasons (which you shouldn't) or you run a lot of hours. I've never had that problem.