Is it a good idea to connect all devices through wifi ?

So as I was meditating I stumbled across this question, is it a good idea to connect all devices through WiFi (at home)

I have like 2 laptops and 6 phones.

Even though I have a bandwidth of 8 Mb/s which enough for such devices and usage, I sometimes encounter this type of problems : When I try to access my router through a web browser (using WiFi ) it doesn't let me even a ping doesn't work, and no internet connection, as if it froze, so I reboot it and everything's back to normal for some time, I thought about the buffer's limit within the router but then I thought that it's really an old router if I do say so myself (D-LINK DSL-2750U) so yeah...is it because there's too many WiFi usage that it can't manage it and freeze?