Getting an inheritance can be fabulous. Giving an inheritance can be an even more rewarding experience. The question remains, when do you give a person their inheritance?
A traditionalist will wait until everything is divvied up in their will and the person receives the money after the death of the benefactor. Practical but a slightly gruesome celebration of death. Grandma died but yay, we get $4000.00.
A more progressive stance might be to give the inheritance while the benefactor is alive. Both persons then get to enjoy the gift. However, you must remember that it is indeed a gift and unless you put stipulations on it, the person is allowed to spend it as they choose.
Depending on the size of the inheritance, you may wish to put stipulations on its use. Common ones would be that the gift must be used for schooling or to help with the down-payment on a house. This will also indicate when it would be appropriate to give the inheritance.
Giving an inheritance to someone too immature to use it reasonably can lead to disaster. While 18 years of age is considered the age-of-majority in most areas, you may wish to delay giving an inheritance until a person has demonstrated the ability to act responsibly.
You should also look into federal and local laws regarding gifts of money. While you want everything to be legal, a large cash inheritance can cause legal or tax issues for the recipient. You may wish to give the inheritance in stages that would not trigger any government agencies. You may also consider discussing the inheritance with the recipient directly to determine if the money would be better spent paying off bills directly or donated to a charity in their name. Educate yourself and make the best decision possible for everyone involved.