There's a lot of ways to get IoT devices connected through to the Internet. Usually they're connecting through a hub (via Zigbee or Z-wave), Bluetooth, or WiFi.  But connecting so many devices can start leading to issues.

IoT Security issues

There are a ton of manufacturers making smart products, but not every one of them are stringent about keeping your security top notch on every device, the proprietary apps they run on, and even the server handling your data. There's so many ways that your data can be lost, so it's smart to know what to do to mitigate the risks.

One way is to get a top notch password manager to store your logins. Shared passwords between sites is an easy way for hackers to get into your accounts and take over.

The other way is to separate out your WiFi network into different networks that don't interact. Some of the high end routers are able to do this, but the one I'm using is the Synology RT2600ac, which is like WiFi 5. The newest standard is WiFi 6 (ax), even going into WiFi 7, but it's so expensive and we're not at the bleeding edge of technology. But the nice thing about this router is that it uses the same interface as the Synology DiskStation Manager. The Wi-Fi networks I have set up are the main network, the guest network, and the IoT network.  It can create more networks, but that would be unnecessary work.

IoT Number Issues

The other issue with Wi-Fi IoT devices is that you can start to crowd the network.  I'm probably sending too much data for regular consumer routers. I've gotten 3 Netgear a nighthawk routers, and I've completely bricked them - can't even try to put an alternative operating system on it, they just won't respond. Maybe it's because I'm constantly sending data through the security cameras. But either way, the specs on the router says that they can usually handle up to 25 simultaneous devices. Between the laptops, phones, video game consoles, TVs, Google homes that we have, we can easily hit that number, and that's without the IoT smart devices.

Thankfully the Synology router can be expanded with another node for mesh networking. Each node is sale to process their own connected devices, and so hopefully splits the connected devices and reduces the workload. I can't say the same for other manufacturers or there, but I'm happy with the Wi-Fi so far.

So to conclude, when buying IoT devices, try to stay away from WiFi devices so your network can be nice and zippy. But if you have to, take precautions to protect yourself and not damage the quality of the network speed.