Leveling first aid

First aid is a must be profession for all non-healers and a handy for even healers.

The training line is pretty simple, since the recipe list is pretty short. However the trick is in switching points. If recipe X give skillup with 25% chance and materials cost 10s, it's better than recipe Y with 100% skillup chance for 1G.

• The start is naturally linen bandage. While the next recipe is available at slvl40, it worth making it to slvl 50, since until this point there is >50% chance of skillup for half the material.
• Heavy linen bandage up to slvl 80 min. From there the decision is made based on price. If wool cloth is at least 6 times more expensive than linen, bring it up to 90. If not, use wool.
• Wool bandage up to slvl 115 when it becomes green. No point pushing it further.
• Heavy wool bandage until slvl 150, where silk becomes available. Silk is usually cheaper then wool, so no point pressing.
• At slvl 150 you have to buy expert first aid book. If you are not high enough level, to buy it from vendor, you have to buy it from the AH. It will be of high cost.
• The trainer teach you Silk bandage. Use it until slvl 180
• Buy the book of Heavy silk bandage and create this item until slvl 210
• Buy the book of Mageweave bandage and create this item until slvl 225
• Go to Hammerfall/Theramore and perform the Artisan quest. You have to be lvl 35, and slvl 225
  
• Continue creating Mageweve bandage until slvl 240
• Talk to the Artisan questgiver and he teach you Heavy mageweave bandage. Make this item until slvl 260. If the price of runecloth is really high, continue to create this bandage up to 270
  
• After slvl 260 you can learn Runecloth bandage from the Artisan questgiver and level with this item up to slvl 290. Expect at least 2x more runecloth than level (60)
• At slvl 290 you can learn Heavy Runecloth bandage and use it until slvl 300
• Buy Master First Aid book, you don't need to be lvl 60 or in Outland
  
• Continue creating Heavy Runecloth bandage until slvl 330. Expect to spend like 150 runecloths for this process
  
• Buy Manual of Netherweave bandage and create this bandage until slvl 360. You will need around 40 Netherweaves for this.
  
• Buy Manual of Heavy Netherweave bandage and create this bandage until slvl 375. You will need around 36 Netherweaves for this. Don't stock Netherweave as this recipe will gray our after slvl 375
• You have to learn Grand Master First aid at the First aid trainer.
  
• Frostweave Bandage is significantly stronger than Heavy Netherweave so it worth creating immediately after entering Northrend. Frostweave cloth will drop from humanoids and will most probably be available in the AH. The skill will be trained at the trainer.
• Heavy Frostweave Bandage will be available for usage at slvl 400. Since there is an extremely stupid achievement to make 500 of these, I guess the AH will be full of cheap (most probably cheaper than vendor) bandages, so you may not need to make a single one, just buy them cheap.