the problem with early planning of trips is the possibility of something important coming up and postponement / cancellation of trip. Not all refund procedures/ rules are that easy. But if it within India by train, book as early as possible to get reservations.
If u want to stay at peace never go to austarlia otherwise they will stab you or will burn alive. Then you will have to take extra holidays than scheduled.
I totally agree that travel is the best stress buster you can have ; and a good trip in 3/4 months is a must to recharge your batteries from the stressful corporate life. Also dont forget to carry your camera! :)
