A common misconception that it’s ideal to have a gathering/crafting combo on one toon. This may be helpful if you have only one or two toons. Otherwise, you could do better!
If you have the flexibility of multiple high level toons, optimize professions. It isn’t necessarily better to have combo gathering/crafting (e.g. mining + blacksmithing) on the same toon. Mail between toons is instant – you need only toon-hop. While owning the chain can be valuable, it makes no difference whether you own it on one toon or across several. Rather, think of how time will be spent and create combos that way. When you’re flying around gathering, you might as well gather herbs and ore at the same time.
For instance, combat-free gathering skills go extremely well together: mining and herbalism. You’ll gather 50% more nodes that way, perhaps more. This can have a HUGE impact on gathering for money.
By contrast, skinning – and farming cloth – both require combat. Might be ideal for a self-healing toon wearing plate, who can work through mobs with little downtime…