Stupidly I just discovered that I've been paying $14/month to rent the router/modem Comcast originally provided.

Obviously that's absurd since I've had Comcast Xfinity TV & cable Internet for 2 years already. So I've already paid something around $330 for hardware that I could buy and own for close to half of that cost. And, the $14/month is recurring so the cost of this just keeps going up at a rate of $168/year for the router/modem alone.

Yes, I'm an idiot for just now doing this math.

That said, I want to buy my own router/modem and stop the $14/month bleeding.

I don't know much about them from a consumer/tech standpoint. I can go to Best Buy and have one this afternoon, I just don't know what I should actually be buying.

The router/modem Comcast provided states that it's a dual band WiFi 802.11ac. I don't know if that tells you anything but it has worked fine for the entire time I've had it.

What would be a good replacement that would be worth the switch?

Any additional advice or insight is also appreciated.

The bone-stock replacement will be an Arris Surfboard, of appropriate generation. No reason not to get a DOCSIS 3.1 from Comcast's compatibility list. There's no good reason to get an integrated wifi/router, unless you just want to do so, to simplify. Most users will want to get a separate wifi AP or mesh system that plugs into the basic cablemodem, often through a separate gig switch - so cable modem into switch, with wifi/router plugged into the same switch. You're probably looking at $100 to $150 for a brand new surfboard 8200 or similar, though you can find deals on older (docsis 3.0) modems that will be pretty much the same, depending on how fast your basic service is. I personally run an older SB6183 modem, because I only pay for 300Mbps service, and it's adequate. I think I paid $50 for it, coupled with an Archer AC1750 wifi-ac router, I paid about $60 for. I won't be getting gigabit speeds, but multi-hundred mbps is more than adequate for my needs.

Things I have zero understanding of in red.

Things I have some basic understanding of but unclear as to your reasoning in blue.

Maybe some clarification from me might help. I currently have the Comcast "Blast" package. A speed test today says I get 209mbs UL/11.30mbs DL. I use WiFi to surf the web from a PC, a few phones and a few tablets. I also use it to stream TV content/movies as well as occasionally play an XBOX 1X. These speeds have proven to work fine with all of the above with no buffering/latency issues. XBOX latency is a bit on the lean side but it's worked pretty good.

Whatever hardware/modem/router/combo I get, it needs to handle the above.

I was apparently mistaken in believing routers and modems are now typically bundled in to a single piece of hardware. To be honest, these terms have to some degree been used almost interchangeably. Based on the explanation below, it appears, to me at least, I need both.

Modem

• Decodes the signal from an ISP.
  
• Connects directly to the internet.
  
• Doesn't set up a local network.
  
• Is not responsible for Wi-Fi.
  

Router

• Establishes a local network.
  
• Creates and manages Wi-Fi.
  
• Splits an internet connection to several devices.
  
• Does not decode the signal from an ISP.
  
• Requires a modem to connect to the internet.
  

You can have an "all-in-one" device which is both a router and modem, or like your current and most common setup, a separate modem and separate router.  The coax cable goes into the modem, the ethernet cable connects the modem to the router, the router sends your wifi.

Where is your hardware located?  How close is it to your Xbox and do you know if your Xbox has an ethernet port?  Do you stream using a smart tv or a device like the Roku or Apple TV, or Amazon Firestick?

What he means by a switch is something like this, which acts as like a splitter : Gigabit ethernet switch.  You can then hardwire devices straight from this, or depending on the router you have, you could be running hardwire ethernet lines to specific devices, like straight to your Smart TV, PC, video game console, printer, streaming device (Roku, etc.)

I have an office in my house with a PC. On the floor next to it is a single "box". There aren't two separate pieces of hardware responsible for receiving and then distributing the WiFi around my home to various devices. On the back of the one box, there are 3 connections. A coaxial cable, an Ethernet cable and a power cord.  

I assume this box is both a router and modem since I receive internet from my ISP and also have a home WiFi network for all devices other than the PC it's wired to.

The XBOX is attached to a 75" Samsung TV in my living room that's roughly 30-40 feet from my office. I'm not overly concerned about hardwiring various peripherals. My phones, tablets, XBOX and streaming content seems to work fine without additional hardware. Kind of a "not broken, don't fix" approach.

Streaming content to the TV is via WiFi through apps built in to the TV. Not Roku nor Apple TV. Never have had connection issues with any streaming content.

In essence, I want to stop renting this "box" at $14/month. That's it. It seems to work fine for it's intended purposes but so far I've paid $330+ in monthly rental fees and that price goes up $14/month, every month that I continue to rent it from Comcast. . Seems owning this modem/router/combo thing would be wise.

With the understanding that "fine" in respect to my set up is subjective, I haven't noticed issues outside of rare latency issues with the XBOX which isn't that big of a deal. It's very infrequent.

Recently moved and had to use cable internet.  I bought an Arris SB8200 modem.  If I were going to use a combination router/WiFi, I would get the TP-Link AX-3000.  Both items get great reviews.

To make life easier, you can copy the SSID and password from your current box and set up the new router the same way.

I went a step further on my setup.  My router is a Ubiquity Edgerouter Lite.  It's only job is routing. I changed my WiFi router into Access Point mode so all it does is WiFi.

Not exactly an answer to your question but something to be aware of.

I had to lease a modem in order to get unlimited data where I live north of Atlanta at the cheapest rate.

I think it was something like $50 a month add for unlimited data with my owned modem or $20 a month for the xfi modem with unlimited data. I just had tech support put it in bridge mode to turn it into a modem only.