Most pocket pets are housed in a cage of some sort which means that all their needs must be met by their people caretakers. They will have no escape from a hot or wet or urine or feces filled area.
You will be responsible for providing a safe, clean and healthy place for them to live in. This is very important! A cage left in the sun, a water bottle that leaks, litter filled with ammonia from the urine, etc. can all be deadly.
Please take your responsibility seriously. Provide an environment appropriate for that particular animal. Know the temperature ranges which are comfortable for them, know if they are burrowers (they need a place to hide which simulates a burrow, dark and cozy), know what they eat and if they have special dietary needs (guinea pigs need vitamin C), know their behavioral patterns and what is normal or abnormal, know their main health problems and what to do if they get sick, provide mental stimulation (toys, running wheels, etc.) when appropriate for their mental health, know what to do if they escape, control noise levels near them, drafts, heat or cold and if dietary changes must be made, make them slowly.