A clock will be constantly visible on your forearm and time will be the only commodity in the world, in which you'll get paid and make payments in.
After the age of 25, you'll get 1 to 75 years of "time" deposited in your account. The clock on your arm will decrement by default as time passes, and increase/decrease as you earn/spend.
When your time expires (the clock reaches zero), you die.
Most people will live day-to-day, only having 24 hours of time in any given moment. Others will have millions of years on their clocks.