It's not really problem for hobby skiing. There's few things why. First, there's not even one single hobby skier who would feel difference between properly prepared skis for WC race and "a bit less properly prepared" skis for everyday's skiing. Once you had skis on your feet for 20 years on daily (or even twice a day) basis for 9 months a year, you can feel even small difference, and most of time, you don't even need stop watches to see which ski is better... even if difference is really small.
And second, it really doesn't matter if ski is 10% faster or not. What matters for hobby skiing is, that you save few 100eur (or $), if you don't spend them on fluoro powders, and you can get another week or two of skiing with this money instead
When it comes to race, every 0.01sec counts, and that's different story, but for non-competitive skiing, it really doesn't matter, so it's no big deal if you skip step or two, or if you use cheaper low or even non fluoro waxes.
It's still important to have skis normally maintained, because it's still much more fun skiing with normal skis, but that's about it.
As far as different brushes are concerned, there's no strict rules about hard or soft brushes. But there are millions of small secrets you learn through the years, and they go from mixing on first look impossible combinations of waxes, to stuff like which brush to use for which snow type. Using softer brush, or even horse hair brush for cold snow and hard waxes is for example on of those things.