I don't necessarily observe that with Windows 10. I usually go 2-4 weeks between restarts, mostly when updates arrive and require it, and I notice no drop in performance over those 4 weeks. I don't hibernate, I just sleep. With Windows 10 hibernate is not even an option on the start menu unless you enable it.
One thing you will notice if you have limited memory and a magnetic disk, is that as you run more programs they will start occupying paged memory. Shutting those programs down will definitely become slower if that happens. Use the task manager to keep an eye on your memory usage and try not to exceed your installed memory capacity. Paging will still happen with an SSD, but it will be much faster and you will notice it less.