I'm on the process of slowly converting my house into a smart home. The first thing I did was getting the house ready by cabling it with CAT6 ethernet cable which run the smart TV's, Wireless routers and security cameras. Keep in mind that most of these smart devices will be using a wireless connection so you will need to have something reliable and with a good range. I have 2 of these
https://www.amazon.com/gp/product/B015PRO512/ref=oh_aui_detailpage_o03_s02?ie=UTF8&psc=1 with a 150Mbps fiber optic internet connection.
I was on the fence of either getting the Amazon Echo or the Google home. I ended up getting the 2nd generation Amazon Echo Dot to test it out and so far I really like it. The number 1 reason I got it was because Echo has been out far longer than google home and they have a wider range of supported devices. Number 2 reason, I got it on sale for $39. I didn't want to spend over $175 on either of the other 2 devices just to find out that it wasn't going to fit my needs. #3, I already use the amazon fire sticks on all of my TV's because I do not have cable so I figured that I would stick with an amazon product.
I also have two Ecobee 2nd Generation thermostats which I love. You can control these thermostats from Echo or your phone from anywhere in the world (I tested this not long ago when I went away to the Dominican Republic and was able to check and change my temperatures without a single glitch). I also like the fact that you can set a schedule and not worry about having to manually change the thermostat every single day.
My next step was getting some lights, I ended up purchasing some of these (again, to test them out):
https://www.amazon.com/gp/product/B01HXM8XHO/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1 I like the fact that these lights do not need a Hub (extra cost and more devices around your house) and you can control them from anywhere using your phone and also with the Echo dot. I installed them on the front porch and some hallways and so far they have been great.
I do not think that having a smart home is something that "will get old." If you only have the Echo and nothing else, then yes, you can only do so much with it "Alexa, play some music" etc. But if you really set these things up, you will find yourself using them more and more. You don't have to walk all the way to your thermostat just to change your temperature "Alexa, change home temperature to 72" done. I have an accent as English is my second language and Alexa understands everything I ask her to do.