Preventive is also "scheduled" maintenance, meaning you try adhering to manufacturer maintenance instructions. Corrective maintenance is a vague term, sometimes perceived simply as repair job or in rare cases correct something thats been found to be flawed and recalled by manufacturer.
If you own some machine or automobile, best to send it back to your authorized service center for reasons of warranty validity and proper procedures as specified by manufacturer. Of course people desire to save money all the time and cost is nearly ALWAYS a primary concern, which give root and risk of compromised work done at 3rd party workshops. Its your call as you own the machine or car.
In my case, I used to DIY maintain my own cars, for reasons, I've studied the authorised FACTORY SERVICE MANUAL, I'm young and energetic, I HAVE the talent, tools and passion for engines and other DIY (Godsent?) I HAVE the confidence, the right place and PROPER tools to do the job. With all these conditions met, I undertook to maintain my cars. Now old aledy.. no proper place, not conducive, lack of energy, so? SEND TO AUTHORISED SERVICE CENTER!.. no brainer! Pay lor!
P.S. I will not debate about the quality of service or complaints from various quarters on authorised service centers. Anywhere or any place, people are sure to complain about something. Nothing really perfect in this world. Thats another story.
I agree about the added P.S. I have had some aging problem with my car sometime back. So instead of sending it to the authorized service center, I sent to my mechanic. He takes care of my tires and does engine repair and wiring as well. When the replacement part arrived, he replaced the bad one. But he took half a day trying to figure why the new part not working. Finally the next door wireman helped solve the issue. Quite frustrating for me to pay him to learn.
Sometimes the parts cost more that what the authorized center charges. Some more have to wait a day or two as they need to place an order to the authorized center.
So I have decided big job or small, I will go back to the center. Free coffee and comfortable wait environment. And at times cheaper and quicker.