I was stumbling through Staples and saw that routers now come in N and AC. I have an N I bought back when they were still kind of new. I use it wired for two computers and wireless for the laptop, Roku, and iPod.
Now when I do speed tests on the laptop I get all the speed I'm paying for. Would I benefit at all with upgrading my router to an AC? The laptop isn't a gaming unit and I don't have much problem with streaming content for the Roku.
Most people only use WiFi as a means to get on the Internet. And if your Internet Speed tests give you what you're paying for, it wouldn't be worth the money to upgrade to AC at this point. So if your Internet is 50 Mbps, the difference between your WiFi being at 450 or 600 Mbps (a newer N router) or AC being 1900 Mbps won't necessarily give better Internet speeds. If you transfer files locally between computers in your home or have a file server or media server, you'll see better performance. But that's internal (local) vs. external (Internet).
ALSO: These units you plug into the wall to help boost/carry the wifi signal---would these be of any benefit and does anyone use them?
Those devices are marketed as "range extenders" and they're technically just repeaters. Sure, they'll work as advertised, but the way repeaters work in radio communication is they will cut your wireless network speed in half yet again. Like
EphesiaNZ said, WiFi advertised max speeds are theoretical and half-duplex. A range extender (repeater) would cut that in half.
I'd use them as a last resort. I'd try getting a strong wireless router first or positioning it more in the center of your home or higher up towards the ceiling. And experiment with the antenna positioning (if it has external antenna). I personally wouldn't buy any range extender.
Some Tips
If you have an Android device, install
WiFi Analyzer. Apple iOS doesn't allow any WiFi apps.
For PC/Mac, try inSSIDer (but it's $20 now). It lets you visualize the channels and which nearby networks everyone is on, so you can choose a channel that has less noise.
1)
2.4 GHz vs. 5 GHz band. Most WiFi (802.11, 802.11b, 802.11g, early 802.11n) only used the 11 channels on the 2.4GHz band, and it gets
crowded. Your next door neighbor and yourself might both be using Channel 6, hurting both performance and speed for everyone.
If you have a dual-band Wireless N router (and your devices support it), I've had WONDERFUL results by switching everything over to only using 5GHz, and I turned off 2.4GHz (or kept one SSID running just for an old printer that only does 2.4GHz). No one in my neighborhood is really using 5GHz, so it's nice and quiet. Plus there's a LOT more channels available, and the channels are wider.
2)
20 MHz channels, 20/40 MHz, 40 MHz. How "wide" your channel/signal is affects your overall throughput. Since the 2.4GHz band only has 11 channels (I'd use 1, 6, or 11 so they don't overlap, but neighbors are clueless), there's no room for 40MHz wide channels, and it's kind of impolite. As a courtesy, I keep my 2.4GHz WiFi at 20 MHz width, and my 5GHz WiFi at 40MHz width so there's more oomph.
Wireless AC only supports 5GHz band, and it also supports 80MHz and 160MHz wide channels, which is how it gets those huge speed increases. But if your iPod, laptops, etc. don't support the latest AC, it's not worth the money to upgrade your router.
I'm personally waiting a couple more years since my N router meets my needs.