Your computer will boot in like 10 seconds. If you think that's a bad idea... then I guess it's your thing. :)
If you don't start up or shut down your computer a lot, and you don't have space on the SSD then don't worry about it.
But either way, you can get programs that copy partitions, and there are programs that are designed to move OSs to a new hard drive. All you do is run the program, let it copy your boot partition to the SSD, then unplug the old HDD, set up the SSD as the boot drive, then if everything works, erase the old HDD and you're set. If it doesn't work, just plug the old HDD back in and everything is still there.
As for the limit to the number of times you can write to a SSD you can calculate it out. If you used your SSD constantly it'd take like 50 years to reach the write limit.