How Often Does Everyone Auto-Tune their PID?

[Edward176]

Just a question to the general members on how often, if ever, does everyone auto-Tune their PID?  I did the set up when I purchased it (Auber WSD-1200GPH PID) to function with my 6 rack digital after I did the dual 500 watt heating element mod. So far its worked flawlessly for the past 2 years, but am wondering if I should be Auto-tuning it yearly, monthly, or ever? So any suggestions would be appreciated.
I would also add, how does everyone do their Auto-Tune? I read the instructions and it gives a vague procedure. Some have with a load of meat, others with a water pan and others suggest a brick. Another instruction says to Auto Tune while smoking your meats. 

[TedEbear]

Unless I change some hardware such as adding an element, I never mess with the auto-tune.  I don't think there's a need to do it unless I notice the temps starting to drift more than a few degrees from the setpoint.

[bigjimak]

The short answer is "rarely".
The longer answer is when you don't like how accurately it's maintaining the temperature. 

While we could go into the Proportional-Integral-Derivative (hence PID) parameters, the essence of applied Calculus, and how they affect the system response that's silly in this application so I ask others wiser than I on advanced mathematics to avoid confusing the issue for others.

In essence, the P,I,D parameters control how quickly the heaters turn on and up as the temperature is dropping and approaches or drops below its set point.  If also controls the ramp-down as the system approaches set point, in an attempt to not have the temperature drop too low when dropping or go too high when its heating.  Meat loat, type of load and especially things like internal fans affect this.

Practically, if I was a long-term roast smoker and switched to a long-term jerky smoker, I MIGHT re-tune.

I would (and did) re-turn when I added my fan to the system because that significantly affected the heating and heat flow in the unit.

Just my $0.02..

[Edward176]

Thanks for the info and input.