Unless you get codes for misfires, then that's the time to have them serviced. Injectors will last a long while if you use a fuel injector cleaner. Yes you can go to Mr. Injector for ultra sonic cleaning if you wish. The benefit is only if the replacements are not easily found. Corolla injectors are easily found.
How Long Will the 2012 Toyota Corolla Last? A properly cared for 2012 Toyota Corolla will last over 300,000 miles, and is one of the longest lasting compact cars on the market. Regular annual maintenance costs are more affordable than the competition. Repair Pal estimates them to be $383 per year.Mine gave up around 100k miles and 13 years. Replace it if you are in this neighborhood. 2001 Toyota Camry 2.2L LE w/ Solara strut tower brace, KYB Strut Plus, Whiteline RSB, Moog end links, Avalon 16'' wheels, Yokohama Avid Ascent 205 60 R16, 145k.