it really depens on the milage of the vehicle and why you want to switch.are you driving more everyday and need to change your oil every month?if the engine has more than 35000 miles on it I wouldn't recommend it.synthetic oil is alot thinner and will find leaks that regular oil doesn't.synthetic oil is also about 65% more expensive for a quality brand.you can increase your oil change interval by about 2000 miles with synthetics because they don't break down as quickly.ask your mechanic what they think.check for any present oil leaks no matter how small.
Yes, you can even mix them.
yes
Yes, you can even mix them.
No, you can even mix synthetic with conventional oil. It will do no harm at all.
No it is fine to switch back to regular oil.
yes, if the car manufacturer dictates that regular oil is acceptable. If your car requires synthetic oil as dictated by your owner's manual, then DO NOT use regular oil. May void warranties if your car is still covered.
If you have kept regular oil changes, no prep is required. Just go and put the synthetic oil in.
yes it is fine but of course synthetic is the best to use if you can. Double check your oil requirements with your owner's manual. If it states that normal oil is okay, then go ahead. If your owner's manual dictates Synthetics, then DO NOT switch.
5W-20 Oil
its the same process as changing synthetic oil, except you use regular oil.
Synthetic oil or a blend of Synthetic and regular oil is much better for your vehicle than regular oil alone. Synthetic oil is MUCH more expenshive. If you change your regular oil every 3 months or 3,000 miles I will be fine.
Yes, you can. It is even sold as a Synthetic Blend.