As long as you are in the 5.8-7.8 (probably even lower/higher then this)range, I would say, yeah ignore it all together unless you are breeding some very picky fish. Strive for stable KH/GH, instead of specific ranges. As long as you don't have any extremes (0 KH/GH or 20+ KH/GH). What you do want to keep an eye out for if you do decide to dose GH/KH, is to take it slow. Big/fast swings in these parameters will definitely impact fish/plants.
Bump: You might want to read up a bit more on the pH fluctuation and Co2. Correct me if I remember wrong, but I believe Tom Barr mentioned that lowering of the pH by Co2, is not the same as other acids/chemicals. This i'm just pulling out of my ass though, so research it yourself or take it with a grain of salt
2nd bump: You might want to check you local tap water supplier. I did, and my tap water contains 36ppm Ca, 0.3ppm Mg and 0.02ppm K as GH. So I need to add Mg and K for the plants at waterchange. I add 5-7ppm Mg and 18-20ppm K. Striving to take out as an exact amount of water each week as I can, and putting in the same amount of minerals each time. To try and keep things as stable as possible. I have a KH of 2.5 out of the tap, when I tried to fiddle with it it just lead to problems for me. Now I just leave it alone and things are tons better, not that all my problems are solved, but thats not related to this. And I use aqua soil, so by the end of the week its closer to 1.5-2 KH. Still no problem for C.Strebai, Cardinal tetras, otos, BNP, Black sakura, amano, platy, zebra danio, SAE's, clown loaches and yoyo loaches..and probably a bunch more I can't remember at the moment that I have kept under these conditions over the period of my aquarium career :P.
Ada Aqua soil and the drifting KH is the reason I'm not using a pH controller for regulating co2 anymore and dialing in the regulator the "correct" way instead. Eliminating further variables as drifting KH, phosphate buffers etc. When you adjust your regulator to say pump out 50ml pr
min, it will do that no matter the KH/PH/GH whatever. With a controller, not so much. Still use it as a pH reader, and to dial in the regulator with a pH drop of 1.2-1.3. Tons easier, and more accurate then pH drop tests, so not a complete waste of money
.hehe, sorry i'm a little harsh on the pH controller, but it's been the devils work for me.