Do I need to upgrade my router?

First of all, I'm not very tech savvy, so the simpler the answer the better. I have a very old Apple router. It was fancy back in it's day, but that was back in about 2007.

Pretty much all of my other technology is new (MacBook Pro, PS4, new iPhones, etc). My internet connection is 50/25 and my home is 2 stories & about 1800 sq ft, so that should give you and idea of what I need the router to do & how much of an area it needs to cover. I stream a lot of HD video & play games online so I need my connection to be fast.

I just realized the router may need to be replaced, but I'm simply guessing that's the case because it's old. What does an old router do? Will it slow down my internet speed? (It doesn't seem like it because when I do a speed test online it says I'm getting the full 50. Does it not cover as much area? Again, I just feel like it might be outdated because it's so old, but it's still functioning. Would I notice a difference if I bought a new router, & if so, what would it do differently?

Assuming nothing has been damaged on the router, it should function as it always has. However, newer technology will always be better as… Well that's the point of developing technology.

If you can't get a signal in some parts of the house then you can either get a new router with a bigger range or you can buy these little devices that boost the internet to other parts of the house if you plug them into the mains. It is worth noting that all Wi-Fi is transmitted by radiowaves, which will never change as they are just a part of physics. There isn't some new technology that means radiowaves suddenly don't get the interference that older technology has.

If you are running multiple devices at the same time, then you may need to upgrade the internet speed.

EDIT: There's an app called Wi-Fi Analyzer, i know its on Android but is probably on iphones too, or something similar will be. This can check what channel your internet is being transmitted. Often they are set to default channel, and if neighbours also have the same setting then your connections will interfere with each other. The app will show you what channel you and everyone is on, so you can change your router settings to transmit via a different channel if there's a clash. Doing so may not only improve your connection but also that of everyone around you.

Another way to speed up your internet on a device is to have it plugged into the router or the main terminal for your internet. This means its not Wi-Fi and so it's only being transmitted through wires which is much faster.

In going back to the question at hand, a new router is likely to have greater capabilities such as a higher range, and less disruption within the router itself, but in terms of once the Wi-Fi is transmitted, the interference through the walls/floors of your house will be the same with a new or old router.

You better change your router.

It depends a lot on what router you actually have. Wireless Standards have gone through a couple of iterations, from B, to G, to N, to the latest AC, and speeds and performance have increased over that period of time.

Sometimes. Because there have also been features like 5 Ghz, which deals somewhat with congestion, a it has more channels (and less other devices using it) than 2.4 Ghz, but that is also vulnerable to some more interference.

Still, if you have just a Wireless-G router, you might notice some improvements from a new router that supports Wireless-N, or the standard that has come after N, AC, if you have any devices that support it, or if you ever get any.

If you have one that's Wireless N, it may be draft-N which means its software may not be great (though I can't say so, I don't know Apple firmware that well), and you may find a newer router has better performance and hardware, because just like computers, a router has a processor and storage inside, and those have increased over time. You might also find that they have better antennas, or other things you like.

If it ain't broke, don't fix it…