NEVER EVER, NEVER, NO NOT EVER.!
Well hardly ever.
It depends how you classify a click track. If you mean a metronome "Beep ding ding ding" then I never use a click track. I have found that I can't get any expression into my playing. But as I am not a drummer or keyboard player, I use midi for drums, piano, horns, woodwind etc... so I do need to sync my guitar / vocal work to a pulse.
I have found, with a little trial and error, that writing a simple drum pattern (the full pattern is done later) of just hi-hat and snare or kick, to highlight the dynamics of the tune allows me to play in sync but not be mechanical.
1. I play along with the simple pattern and note where it is knocking me out of my groove.
2. I adjust the pattern until it is just enough to groove to, but simple enough as to not distract me. After all it's only there to allow me sync midi stuff to recorded audio.
With practice it normally only takes a couple of times round the loop to get to a point where the "click" track is felt and not heard. But it is worth spending some time doing this. It lets the song define the beat, not the other way around.
Of course this is for recording purposes. To get to this point I really need to have a good feel for the song.
Hope this helps.
Mihkay