Other than for illegal activities I can't think of a realistic case that can use a gbit connection on a consistent basis.
With a lot of work at home and home lab situations, even a 1Gbps symmetrical connection can get saturated. A couple of busy ipsec tunnels and some regular file transfers can eat it pretty quickly.
So I manage 4 different connections in 3 different locations, 1 of which is a business. Beyond just the connection, there's also your network that it connects to--your router, switches, etc.--that makes a difference too in the overall experience.
The limiting factor for what we are needing our connections for is the upload bandwidth because I'm using ipsec vpn tunnels across all of mine, and the upload bandwidth becomes the limiting factor--even when the download is quite fast.
I have the following: 600/15, 500/50, 110/10, 110/10. The two 100/10 connections are with the same isp and connect two sites only a few miles apart from each other. Performance there is pretty solid since it's not having to traverse the entire Internet.
On the other hand, the 600/15 and 500/50 are with different isps and span the entire US, so even though they are much higher bandwidth, the 100/10 tunnel can 'feel' faster.
The main thing to make sure is that you are getting what you are paying for, and that you really need that much or are finding value in it. There are very basic plans available from almost every isp between 5-30Mbps for just $30-$40/mo. But when you get almost 10x the bandwidth for $20 in some cases, these don't present a good value and are really intended for those that literally cannot afford much more.