Well, if you have a hamster, you should probably count how many days/months/years you had him or her, and they should be older than that. A way to tell if a hamster is young is that he or she will be more hyper.
Old Hamsters are Lazy, also have bad teeth then usual
Hamsters' weigh is depended on its diet,size and its age.
easy just remember when you got him and how old he was then add them together then take away from the date today
They get a lot fatter.
look at its privates
Lazy and bigger nipples means ready to give birth
Baby hamsters leave their mother at three weeks old.
hamsters can only live for three years so they die when they are 3 years old
This link should tell you everything you need to know about hamsters! http://hamster-care.com/breeds.html
They have teeth when they are born.
When they open their eyes.
yes As someone who has been on the wrong end of a hamsters teeth I can most definitely tell you yes they do.