If you wish to play Rachmaninov's 2nd symphony (which is long and tiring), along with a concerto and an overture, making up a 2 hour concert, do not do this on the hottest muggiest stickiest most vile day of the year when the air conditioning in your concert hall is broken. As soon as the stage lights are switched on you will sweat buckets before you've even started playing, and when you do play you will sweat even more and will be unable to keep your fingers on the keys. Also do not do all of the above on a day when they are digging up the train network and you have to leave the house early in case your replacement bus service doesn't turn up - just to spite you you will be stupidly early and have to sit in the hot sun for 2 hours. You will then have to spend your bus/train combo journey home sitting in your own sweat in desperate need of water. You may also develop an interestingly large blister on your big toe.
Really, really not recommended.