Mobil 1 EP Synthetic shelf life...

The shelf life should be indefinite.

I've used stored oil that is over 10 years old with good results.

 

That's not that cheap. It's $3 to $5 less than walmart's 5 quarts price. Is it worth it? 1 Starbucks is more than that

 

Shelf life should be fine but you already have a 1 year supply. You want to have 3 years worth of oil? Do you buy like this when toilet paper goes on sale?
Oil always goes on sale

 

Yep;

I'm still using computer printer paper that I bought for less than $10 for an entire box of 6 reams. Those boxes were purchased in 2000.

 

They were selling those with 10 reams at that price in 2000. You got ripped off

 

I've stored the Mobil-1 in my garage a long time, but I've finally used up my inventory.
You did not say what grade you had, but what I've noticed is the formulations get updated, or at least the ratings change.
For example, I believe the 5W-30 now has ACEA A1/B1 A5/B5 rating which is quite top notch. But my recollection is that the older bottles did not have the same ratings.

 

It would be different if they were giving the oil away really cheap. The savings is only $6 per 5 quarts/1 oil change/half year. $6 saved in half a year is like saving $1 a month. Doesn't make much sense to me.

Imagine if you upgrade to an electric vehicle that doesn't use oil?

 

At one point about 10 years ago, I hit upon a WalMart store that decided to no longer carry Mobil 1. They had twenty 5 quart bottles at $6 each. I bought ALL of them, and used the last bottle just a couple of years ago.

 

Well I would have done that too. That's not the same as what the OP is doing