Source: Apple.    

It's time for the annual rite of long lines and shiny new iPhones. Apple (AAPL -1.22%) is rolling out the iPhone 6s and iPhone 6s Plus to stores on Friday, and there's a good chance you or someone you know will be a part of the phenomenon. 

There are plenty of reasons to believe there's an iPhone 6s in your near future. Let's go over a few of them.

1. Some carriers are encouraging annual updates
The country's two leading carriers are shying away from subsidizing smartphones. The transparency in pricing may make people hold on to their phones longer once they're paid off -- it's no longer a matter of paying the same rate even after the two-year commitment is complete -- but that's also opening the door for smaller carriers to differentiate themselves. 

Sprint (S) and T-Mobile (TMUS 0.92%) are doing that with plans that offer annual upgrades. Sprint is even calling its plan iPhone Forever, branding it specifically to Apple's line of smartphones. Sprint -- and T-Mobile's Jump On Demand -- are encouraging regular upgrades, unlike its two larger competitors where customers pay substantially more a month for the right to trade up every year.

2. The new device is a game changer
Apple generated a lot of media coverage last year when it introduced the iPhone 6 and the iPhone 6 Plus. The iPhone 6 was bigger than the iPhone 5s and the iPhone 6 Plus is naturally bigger than both of them. Apple is sticking to the same form factor this time around, but it doesn't mean that it's the same device.

Perpetual iOS updates improve the quality of all applicable devices, but that doesn't mean that an iPhone 6 owner is a software update away from the equivalent of the iPhone 6s. There are several hardware improvements, and we're not just talking about the more powerful processor and the better cameras particularly the front-facing one that will now take reasonable selfies when turned your way.

A major addition to the iPhone 6s is 3D Touch, a pressure-sensitive screen similar to the Force Touch technology that Apple introduced earlier this year with the Apple Watch debut. This will give users a new way to engage with their devices, and when that's worked into enhancing apps folks with older models than the 6s will be kicking themselves. 

3. You may as well upgrade now
Apple has made it a habit of pushing out annual updates to its iPhone line, and while that makes it easier to forgo an upgrade cycle -- you can swear off the iPhone 6s and hop on the iPhone 7 next week -- human psychology doesn't work that way. Apple continues to sell iPhones all year long, even well into the summer when everyone knows that a new iPhone will hit the market, shaving the price of the current model by $100. 

The siren song of the iPhone eventually wins, so why wait? Buying the iPhone 6s now gives buyers the maximum time of enjoyment before the iPhone 7 makes it inferior. See you at the Apple Store next Friday.