Should I Change Oil every 3,000 miles so Car Doesn't Become a Leaker?

If by "leaker" you mean that oil leaks externally from the engine:
My 2007 Prius has 355k km (220k mi.), I change the oil every 25k km (15k mi.) with synthetic longlife oil and an oversized filter, and the engine is absolutely dry on the outside.

If you mean "consume", or "burn" oil internally:
120k km (75k mi.) - first noticed a little oil consumption of about 1 liter/50,000 km (30,000 mi.)
180k km(112k mi.) - suddenly dropped to about 1 liter/35,000 km (20,000 mi.)
355k km(220k mi.) - gradually dropped to presently about 1 liter/8,000 km (5,000 mi.)

That sounds like normal use to me. But if you have oil of unknown quality, you might want to change it at 5,000 miles or six months, whichever comes first. If you have top quality synthetic oil, I think Toyota's recommendation of 10,000 miles or one year, whichever comes first, is OK.

 

It'd in your manual. I forget the page.

 

I was a firm believer in every 3k for the longest time. On my summer "fun" car I often changed the oil before 3k, just because I didn't put that many miles on it. It always got changed once per year with Mobil1.

Anyways on my Prius the car tells me every 5k, dealer says every 10k is ok but with 236k miles it is using oil so I am debating on what to do. I have been checking the oil level every 1k and adding a bit as needed. 0W20 Mobil1.

3k is too soon. Go at least 5k.

 

How many miles when you noticed the consumption starting? How much are you adding as "a little bit" at 1 k mile increments?

Have you attempted anything to slow the oil consumption? Any engine issues with your Prius?

 

FWIW
If the OP means to stop potential leaks from rubber seals.....
Driving and getting the car hot before storage or non use I'd say is better preventative maintenance than 3K oil changes.

I'd also say synthetic oil usually says within spec for two years or 10K mileage.
Black Stone Lab oil test would confirm for the OP specific region.

Yet for fun, not pocket book, why not change every 3K?
Would cause no harm.

 

Use Trip Meter "B" for oil change.

 

I've got two Mazdas that were purchased new off the lot. Both have had 5,000 mile oil changes since new with conventional oil (until the last oil change, I switched to synthetic). 2004 Mazda 3 with 195,000 and 2010 Mazda 5 with 135,000. Neither car visibly leaks oil and neither car shows any noticeable change in dipstick level over 5,000 miles. The manufacturer's suggested OCI on both cars is 7,500 miles. And think of the difference in the amount of work those engines do compared to what the Prius ICE does.

3,000 mile OCI is made up by the oil change companies and mechanics to make more money.

 

or make sure Trip A is on the display and hold down the mph/kph button when turning the car on and keep the mph/kph button held down until the maintenance reminder is done resetting.