Turkey Baster power steering fluid?

[apollo18]

Hey Guys! I'm gonna get the fluid in my truck changed by a mechanic soon. He's gonna do diffs and transfer and hopefully brakes too. I'm pretty sure the power steering fluid is 10 years old. My truck is a 2007. Gm says the fluid lasts forever but I wanna change it. 

 

Can I just do the turkey baster method? Siphon out the fluid, add new, drive around, siphon again, add new, drive around, do this a couple more times and then done?

 

or should I get him to do it his way (whatever way it is). 

 

Also should I just use gm fluid since it works great already with it or use amsoil or soemthing