Scam or Legit? Oil change

I have a Toyota(84,000 original miles)and it takes full synthetic,very little city driving, mostly highway at night & my oil change sticker has every 3 thousand miles.
Sometimes the young employees gets the milage wrong or he's doing it on purpose. I thought full synthetic oil was 5,000 miles before your next oil change?

Correct.
However, depending on other factors it could be appropriate to change every 3 thou.

The key is how dirty the oil is that is being drained out during a change regardless of synth or recycled dinosaur.

If it's dirty dirty, change it sooner next time. if it's only moderatly dirty you've got the mileage timing good.

If it's not dirty at all, you could probably wait another thou till next time.

However, it's a rare mechanic that will even mention this concept to clients.

So here's an example: Synthetic. But he tows horse trailers at least once a month and otherwise runs hard. So every three thou. And, if he and the posse take a run to Denver, Chicago, Kentucky or even Katy, TX he gets an oil change the day after he gets home, regardless.

So how hard do you push your Toyota?
Note that with 88 thou on it, I wouldn't wait for 5 thous. Maybe four.

So ask the tech how dirty the oil was. Have an AED available as he'll fall over in stunned surprise.

Adding to the sage advice of Unique-Carpenter: Keep a small notebook in glove box and write down the mileage for each oil change. It is quick and handy.

The information about the type of driving that you do being a major determinant is spot on. Having said this, changing your oil more frequently than it needs to be changed is wise. The more frequently you change your oil, the cleaner it will be, and the longer your engine will last, generally speaking. I change mine every 3000 miles or so. I do a lot of driving for my business, mostly highway miles.

Keeping your engine well maintained is the way to go. Also, have them change your coolant every once in awile as well as a form of preventative maintenance. When it is changed have them change the hoses. It is a relatively simple task for a decent mechanic.

Hope this helps,
jpb

Everyone's opinion differs & this is just mine. Depending on your specific model but Toyota recommends changing oil every 10,000 miles on the majority of their vehicles. I wouldn't wait that long unless I was also using a bypass filter.
3000 mile intervals was the standard recommendation for conventional oil.
Naturally a lube shop is going to recommend shorter intervals along with every other service they provide (air filters/other fluid flushes/etc) to increase sales. They always exaggerate when recommending services, especially if they think you have little or no automotive knowledge.
I use full synthetic & change it every 5000 miles or yearly, whichever comes first.
Your oil is probably still translucent at 3K miles.
Stop & go (city driving), dusty air & heat affect oil most.

How do you know its dirty without oil analysis? By rubbing it between your fingers and the color of it? Lol. Running synthetic and changing at 5000 miles is pissing off money. I run conventional 5-7500 miles easy . Never a problem.Probably could run it longer.