Members generally feel more ownership and involvement than donors. Members may have an expectation to be asked to contribute other things in addition to money. Some of the things they may contribute are volunteer time, political support, expertise and influence. If these things would benefit your organization, then consider starting a membership program. However, if you really just want money to do your work, then a membership program may add more administration for little added benefit. In that case, look for other ways of showing your gratitude for the money that donors contribute. Donors feel involved and hopefully feel appreciated, but they usually have no expectation of being asked to give anything besides money and feel little ownership of your organization.