There are no service books on these cars have to wait for the computer to post a message for maintance
Much can depend on the type of plugs used, type of driving involved, and whether other symptoms may be present. (rich running, CEL on, oil consumption, fuel type, and so on)
Generally speaking, plain copper core plugs are often good for 30-40k miles with platinum and iridium good for 50k and more; all depending.
The modular Fords recommend 100K miles…But by that time it can be difficult to remover the old plugs without breaking them off or stripping the threads…So lets just say with platinum plugs 60K miles is a reasonable interval unless some external problem dictates replacing more often…
If your owners manual no longer lists service and maintenance requirements, the FACTORY service manual for your car will contain all the information you need to maintain your car…
I think all plugs should be pulled and inspected every 30k miles. Plain copper core plugs will need replacement around this time, and if you have more durable plugs like platinum/ iridium, it still doesn’t hurt to take a look and see how they’re doing. An experienced mechanic can learn a good deal from inspecting a spark plug and possibly even identify problems…eg excessive oil burning, a leaking head gasket that’s letting coolant into a cylinder, etc.
If the plugs are good, well, it only took 10 minutes to pull and inspect them. And, it helps keep the plug from getting seized into the head, which can happen if the plug is left in the head for too long.
I have a Haynes manual for models up to 2005, and the 2006 4-cyl is the same engine. The recommendation is to change them at 105,000 miles or 84 months, whichever is first. You have about one year left unless your mileage is over 105,000. If your gas mileage has not dropped much in the last couple of years, you can probably wait. But it should be very easy to check the plugs on a 4-cyl.
From Honda Shop Manual 2006:
Normal Conditions:
176,000 km (110,000 miles), 6 years
Severe Conditions:
Same as Normal
I never liked the 100k+ change interval, because it’s just not wise to leave plugs in that long without breaking the threads loose. They can become seized. The 100k+ interval recommendation is based less on good engineering, IMHO, and more on marketing, because carmakers figure it’s a selling point if they tell buyers theu don’t have to change plugs for 100k miles.
Make your own call, but if it were my car, I’d take the 10 minutes to pull the plugs and inspect them.