So here it is July and this is how the filter cover has worked. This is what the cover looks like each time I take it off to wash it. I wash it once a month.
This is how the actual filter looks after 6 months of use. Just barely starting to build up dust. It actually looks denser in the photo than it does in person. I will change the filter at this stage and use the next one for 6 months with a cover.
For comparison; this is the other filter to my furnace after only one month. It did not have a cover for it.
So the cover is a good idea in my opinion. Now I need to make a cover for the second filter. I will save about 4 dollars a month by reusing the same filters. I looked at the price last week and this type filters were selling for 1.99 each. Changing only twice a year means I can keep about $40 a year for other things.