Carry as much as possible on the trip to Leh as the month of April and May are different from the rest of the year. During these months Leh is usually out of supply and usually sustains on what is left over. Basic things too are difficult to find during such period.
1.) First and foremost important thing is to get acclimatized. Atmospheric pressure in Leh is low and the body needs to be adjusted to it. High altitude and low atmospheric pressure should not be lightly taken. Thus, it is always advisable to reach Leh via road. In this way, the body does not have to experience high altitude. Increase in altitude takes place gradually. Irrespective of whether one has chosen to visit Leh via road route or a flight, make sure to rest in Leh for a couple of days before visiting places of higher altitude nearby.
2.) Carry oxygen cylinder especially when visiting highest motorable road in case if suffering from breathing problems.
3.) Carry warm clothes. Whether it is jackets, sweaters, thermal wear or socks, caps and muffler made of wool, make sure to carry enough of them to keep you warm. Goggles, lotions, lip balms, sun hats are also advised to be carried along.
4.) Carry medical kit which should contain medicines for fever, dizziness, headache, stomach ache, vomiting, a few bandages and other medicines which an individual takes if suffering from the specific condition. One can find medical stores in Leh. However, if travelling to nearby places, one may find it difficult to locate one.
5.) While on sightseeing make sure to carry enough water and eatables along with you. Do not drink heavily or smoke to dehydrate the body. Dehydration at such high altitudes can bring in serious problems.
6.) Carry printouts of hotel reservations and tickets. Access to the internet is a challenge and thus carrying copies is advisable. Do carry photo id and photos of passport size as visiting a few areas in the region do require a permit.