Working with energy, Intention

I have heard it said (and, alas, have also used the line myself) that Intention is more important than knowledge when working with spells and energy.

Now that I'm a little older and wiser, I have to amend that statement. While it may be true when you're working with only your own thought-energy, it gets less true when you use tools (including words).

For example... let's say that I Intend to fix a piece of heirloom furniture - one of the pegs has snapped from age.
Before I go to the hardware store, I need to know the diameter of the hole and/or peg.
When I get there, I need to know what they have in stock, and if the tensile strength of their stock will hold up in the application.
After I get it home, I need to measure and cut the dowel to the right length.
Once the peg is made, then I could tap it into place to fix the furniture.

I could ask the clerk at the store for a variety of things, but only one would be the correct object to ask for.
I could use several instruments to measure. I could use a ruler, a bit of string, or even my thumb. Each have the possibility of working, but there's one that would work the most effectively.
I could use several tools to cut the dowel. I could use a saw, a kitchen knife, or even a thin chain.
I could use several different tools to tap the peg into place. I could use a high heel shoe, a screwdriver, or a mallet.
I could use a dowel that is the wrong diameter, and force it into place, anyway - and it could have disastrous consequences.
I could use a sledge hammer and try to get the peg in place with one mighty swing rather than several gentle taps with a mallet - and it could be equally as detrimental to my cause.

You get the idea.

Although I Intend to fix the furniture, I could end up spending a lot of resources (time, effort, money) unnecessarily. It's possible that I would give up before finishing the project. It's also possible that I could ruin the furniture rather than fixing it.

Conversely, I could have all of the materials and tools available, but if I do not have the Intention to fix the furniture, it will not happen at all.

Therefore, we can deduce that Intention may be the most important aspect of working magic, but it will not change the matter-form or energy of a tool so that it will be the most appropriate for the working.