Which Spark Plugs and When to replace?

Does it use:
- Professional Iridium Spark Plug
- Rapidfire Platinum Spark Plug
- Professional Platinum Spark Plug

These were AcDelco - I believe RockAuto has best prices for NGK/Bosch/Denso too.

Which brand should get? Iridium or Plat or Double Plat?

I bought the car with 85k - now 100k in 2 yrs, When is a good time to change? It starts fine.
2010 Mazda 5 Sport
What year car?

I usually look up the part number and buy from the dealer or get the equivalent from the same oem manufacturer.
(former) 2006 Mazda 5 M/T
I've had excellent service in late-model Japanese engines (Mazda, Honda, Toyota, and Subaru) from iridium and double-iridium plugs from NGK, Denso, and Autolite.