| Explosif, I use a Rena XP3 on my 180 for extra filtration with good results. I do clean it every single week no exceptions. That may be overkill but it works for me. Each tank is different so you will just have to see how dirty it is at different time intervals.
The Rena is a good design in that it is easy to clean with the quick disconnects. I use the extra basket for carbon which I place in a reusable mesh bag. If you use a micro filtration pad, you can save yourself some money by buying the Rite-Size bonded filter pads and cutting them to fit. I sheet yields about 6 pads so it is worth the little effort. | 
