which would be wheel bearings.

#1: As for struts, if the car isn't "bouncy" at the front, they're probably OK. If it bounces at all they need replacement.

If front wheel drive, could well be the ball joints (constant velocity joints) in the axle shafts. These will make noise before you can feel any slack on a lift. When they get real worn you start getting some vibration at higher speeds which varies with how much power you are applying and whether you're turning right or left.

#2: Axle shafts are generally replaced with refurbed units that cost about $80 each for the cars I've had - around $120 to $150 with labor (easy to replace on most cars - but not all).

#3: So long as you aren't driving an MG Sports Sedan (1960's) noise from axles isn't dangerous - you'll get more vibration than you can stand long before they give up. Those MG turkeys had rubber constatnt velocity joints and they could kill you. It was also the only car I've ever heard of where the engine would be destroyed in a few miles if you left the dip stick out. Alex Isogones was supposed to be a great auto designer, but I have serious doubts.

As for identifying the source of the squeak, reliability is impossible. Automobile noises are highly deceptive until they get really, really bad. Often it's hard to even say which side they come from.