I'm putting together an ARF Trainer after 12 years out of the hobby. I still have servos that old and when I turned them on they were buzzing and clicking but I think it could be from the pushrods being at an angle causing some binding but I'm not sure. How important is it to have the pushrods to line up to the servo horn? Are the servo's just too old and buy new ones?

I noticed the same thing with the brand new servos I put in my first plane. It seemed like they would buzz when I first turned the radio on, but would stop after I operated the controls. They still do it from time to time, but I've quit worrying about it, as long as I know nothing is binding, etc.
Glen

You should try to get them as quiet as possible
The humming means that some pushrod is pushing or pulling on the servo arm making the servo motor "fight" to keep centered.

It's very hard to get them all totally quiet, but if you have some spare time, sit down and adjust the linkages so you get as little resistance/bind as possible...If not for anything else, for peace of mind

...I don't know about old servo reliability, but perhaps some new 12$ servos will be cheaper than a crash because the old ones decide to go and die?

Try disconnecting the servos from the pushrods. If it still does it, it could be a problem, depending on what "it" is.

Some buzz or chatter with a freshly charged battery pack that goes away quickly isn't a big deal. Some servos can get a bit over-eager when they get a higher than normal voltage. And that effect can vary from servo to servo with in a brand, it's partly a function of the tolerances of the parts inside the servo, espeically the pot.

An actual "click" noise sounds bad to me, it might be a bad gear in the servo, or some kind of pushrod binding. But with out hearing it myself, I can't say for sure, obviously.

If the buzzing goes away when you disconnect the pushrods, then you really need to look at your linkages and reduce the friction and get rid of any binding.

Keep in mind that any constant buzzing is likely drawing current from the battery pack, and will shorten the flight capacity by a LOT. So keep on constant check on the pack's voltage.
Dennis-

How Do you adjust the linkages? and what does binding mean?

Binding means that a pushrod or a linkage is putting stress on the servo arm.
If the pushrod is bent or too short/too long because of the installation it might constantly pull or push on the servo arm making the servo motor fight to keep centered.

Adjusting the linkages is a way to get rid of the binding, e.g rotating the clevis to give more slack or tightening it. You can also change to a more appropriate lenght on the servo arm or bend the pushrod to releave stress.