Here what precautions I should take while using arduino plugging it for long up to 5 hrs. And uploading multiple sketches one by one without removing the other wirings from pin header is it okay or not because while doing this I observe that sketches like digital serial read blink and fade these stopped working on board and whenever I connect it with breadboard the circuit doesn't work but when I unplugged arduino and then uploaded a program and rewired the circuit for all three then they work fine what was the reason please tell
I will try reading this once you put punctuation where it is usually required in English.
Weedpharma
It should not be a problem running an Arduino for 5 hours.
There should be no reason to rewire a setup.
There are however some items, which when connected, will prevent an upload from succeeding.
If you are able to upload, but the sketch "stops working" by which I will assume what u see in serial monitor is not updating, then close serial monitor and open it again. The sketch should restart.
Alternatively just press the reset button on the Arduino.
Are you using pins 0 and 1 for your circuit?
That may be interfering with the uploading of sketches.
If you are, just use another couple of pins instead.