Relays, to diode or not to diode

I would like to know the following about Relays (SPDT) units:

1) When do you use the internal diode (Clamping diode) style, sometimes, all the time, or never?

2) What wire (alarm module) do you use to control the coil 86 or 85, is there a Rule of Thumb?

3) Can you use the non internal diode type all the time, just to make the choice easier?

1. I never do and if I need a diode I always use one inline that I install ( most of the time it's a 1n4001 1 amp diode )

2. There's really not any difference ( if there's no diode ) but if you want to play it by the books, 86 should be (+) and 85 should be (-) with the diode cathode band facing pin 85

3. Yes, that's what I do.