I use two types of covers that have worked very well over the last 7 years. One is a stiff foam like baffle insert that is in the shape of the gutter. I bought these at Sams Club a number of years ago for cheap!
https://www.samsclub.com/sams/gutter...rod14860272.ip
I also use on top of these baffle the cheap aluminum serrated covers. The internal baffles help support the cheap aluminum covers and pine needles stay out.
http://www.homedepot.com/p/Amerimax-...Q&gclsrc=aw.ds
Yes once a year you should sweep off the covers but that is pretty easy. I have never taken them apart for a clog yet!
Dan