My first thought is tie rod... Thats whats wrong with my car and the stuff is REALLY similar...
With constant changes like that I would say more something has worn out. Jack the car up and see if there's play in the wheels.
Now if you move the wheel and it has play from left to right and EVERYTHING, Like I mean the rotor, wheel, brake caliper, steering nuckle, moves then you need a tie rod end...
If you get play up and down and everything moves
then it's a ball joint
Finally if you get play and just the wheel and brake rotor move then you need a wheel bearing.
Now of course the easiest way is to have someone watch the tie rod end/ball joint to see if they have play when you wiggle the wheel, or if you have larger rims that have alot of openings you can just look at it when you wiggle it