Lol? Soloing nature runes is about as fast as world 16 airs, meaning soloing is better as you get more money. You want to use fast free laws to get 91 as the faster you get it the more time you can spend making back the money with extra time left. Let me put it easyer. Lets say two people have 54 runecrafting, one desides to use fast free laws to get to 91 and the other picks to solo until 91. The first 200 hours of so the fast free law guy will be in debt as he has to pay for the essence, while the solo guy is making a steady profit. After that the fast free law guy (with 91 runecrafting) will start a rapid increase in profit. At around 500 hours of runecrafting both peple will have the same profit over all, but one will have 91 runecrafting and the other dosn't, the one who dosn't is the solo guy. Now for another 100 hours the fast free law guy is making tons of money when the solo guy is still making the steady profit. Once the solo guy gets 91 they will both always make the same amount of money but the fast free laws guy will always be a 100M or so in more profit in overall hours then the solo guy. So pretty much if you can spend the money on fast free laws do it, it will help you in the long run so very very much. (How 100M much :D )