So, if I say "His voice sounded like and old wooden door" that gives the reader something to hook onto, something they can pull from to describe to themselves what it sounds like. But should I do this all of the time, or just some of the time? How much is to much, or is there no to much?
I'd argue this to very much be a matter of POV. The narrative should be in line with your POV character for that particular scene. Given the circumstances of the scene, the character will notice certain things and not notice other things. If it's a fast-paced scene, the character will be too busy focusing on the immediate happenings to notice the environment around her/him. Likewise, if it's a slow scene, the character may sit back and take it all in. What's important, however, is that you stay within the voice of that POV--if the character is an English professor, I'd expect a more observant and descriptive narration. But if the character is a used car salesman, I'd expect a significantly different voice. Same goes for hipster, or teenaged kid, or street thug, or Supreme Court Justice, or what have you. What you choose to describe should be dictated by what the POV would realistically describe in that situation, written with the POV character's voice in mind. That way, all your descriptions have the added functionality of showcasing your character. You can use that to all sorts of ends. Just my couple of pennies.
It depends on the personal preference and style of the writer. There's no right answer here. xanadu brings up some good points as well.
It's a good question. My take on it is this: if readers start to notice you're doing this simile thing, then you're doing it too often. There are lots of ways to get across something about how a voice sounds other than always comparing it to something else. It can be demanding, or menacing or the accusing tone can make the hearer cringe or....well, lots of things. In this case, I'd not say 'sounds' anyway, because it's too vague. Unless his voice is saying "Skreeeee eeee" it won't SOUND like an old wooden door. His voice may creak like an old wooden door, though! If you're going the simile route, I'd be as specific as you possibly can.
It's definitely tricky. I'd say less is more. Also does it work for your scene, tone and style of your book or is it just ornamental? I looked back at some of the metaphors I created for an old story I wrote years ago and realized my mc was comparing things he had no understanding of ( it took place in the future. ) I cringed realizing all my 'pretty' metaphors were ridiculous. The good thing is you do have drafts to realize when things don't work. So in my book it's not wasted words, it's just more learning. I also agree with Jannert - you want a metaphor or simile that cuts to the chase rather than something that needs extra details to explain it.
I agree with those saying you need to be careful with similes - in this case, I'm distracted by trying to figure out whether it's the door itself that makes the creaking sound, or the hinges, and whether it actually matters whether an old door is wood or something else, given that I'm pretty sure it's the hinges that make the noise, and then wondering whether maybe the weight of the door material would have an impact, and... and I'm out of the story. So, use figurative language as a spice, not as the main flavour, and make sure your spices make sense!
I'd say that there can easily be too much. And you don't necessarily have to reach so far away from the actual sound to give the reader something to draw from their own experience. "A painful rasp...", "A smoker's hoarseness...", things like that, still let the reader draw from their own experience. In fact, I wouldn't be surprised if a lot of readers, especially young ones, had rarely or never heard the grinding hinge of an old heavy door.