Does the galaxy s5 lag after using it for a couple of months?

I've had mine two months and never had a problem... I restart the phone maybe once a week just to keep it running smoothly
 
No lag, but as some people mentioned, make sure to turn off animations, clear your cache, and turn off & disable any useless applications in the app manager.
 
I am using S5 duos sine 5 days and it's really smooth and fast...though I have limited apps installed...battery life is great that's it's new with 18 hrs with heavy use...I am really happy with this phone...One of the best android around

i'm curious of your on screen time out of that 18hrs.
 
Is it a good idea to get the galaxy s5 now, or should i wait and get the 2014 moto x gen 2?

Go for the new Moto X. My S5 has become a huge pain in the *** and I'm counting down the seconds until Friday when I can get my iPhone 6 Plus. But on the Android side, I bought my boyfriend an original Moto X a while back and it's been a trooper. I much prefer his X to my S5.