I have bought an OBD2 Android. I saw many parameters in that. I was confused. But I want to know which will my car needs new sparkplugs? of course by OBD parameters.
There are no OBD parameters that specify, or even remotely hint to a particular time to change spark plugs.
The best gauge of spark plug health is to pull one ans "read" the color, deposits, and electrode and insulator condition.
Another simple method is to replace conventional spark plugs every 35k miles, Platinum plugs perhaps every 50k-70k miles, and Iridium plugs every 75k-100k miles. Your Owner's Manual will suggest a change interval.
There are several things that could shorten the lifespan of any type of spark plug, but the only sure way to tell is to carefully examine each plug. Even a non-contact firing voltage probe can only indicate a problem on that cylinder; which may be due to plug, coil, or both.