Sort of.  You can wash them as often as you want, but every time you do, you're going to bleed more dye out.  The more dye you bleed out, the less contrast you're going to see in the bend/wear areas.  This doesn't really affect fit at all, but it does change the appearance to varying degrees.

I rinse in cold water before I wear them, because otherwise you get dye on EVERYTHING.  Literally.  If you spend a lot of time in an office chair, you'll get dye on it.  Anything that you keep in an unlined pocket will get dye on it.  Your shoes or boots, where they rub the denim, will get dye on them.  Sanforized denim will exhibit this a little bit less, because there's moisture applied during the sanforizing process, but they still lose a lot of dye until you rinse them.  Cold water pulls less dye than warm, so you don't see quite as drastic a change.

Don't run them through the dryer, unless you need/want a little shrinkage.  Also part of why a lot of selvedge jeans come unhemmed.

I wash them when they start to smell bad

You're kind of missing the point.  They can be cared for however you like, but if you have a particular "look" you're shooting for, then certain things have an effect on that.

They'll shrink if you run them through the drier and put the coals to them, but so will plenty of other things.  If you want to chuck them in the washer once a week, fine.  If you don't, fine.

I didn't read all the way back through this, so it may have been mentioned already, but make sure you're hanging them after you take them off so they can air out and dry fully.  Otherwise you'll blow the crotch out in about a year