When is it okay to overthrow the government according to Jefferson?

From the Declaration of Independence. Not only do you have the right to overthrow your government, it is a responsibility placed on us by a founding fathers. If our government betrays us, acts other than in accordance to our wishes, or we feel changes need to be made, it is our obligation to do so.

Selected quotes by Jefferson about 'rebellion':

• "What country can preserve its liberties if its rulers are not warned from time to time that their people preserve the spirit of resistance? Let them take arms. The remedy is to set them right as to facts, pardon and pacify them." --Thomas Jefferson to William Stephens Smith, 1787. ME 6:373, Papers 12:356
• "The spirit of resistance to government is so valuable on certain occasions, that I wish it to be always kept alive. It will often be exercised when wrong, but better so than not to be exercised at all. I like a little rebellion now and then. It is like a storm in the atmosphere." --Thomas Jefferson to Abigail Adams, 1787.
• "Whenever any form of government becomes destructive of these ends [i.e., securing inherent and inalienable rights, with powers derived from the consent of the governed], it is the right of the people to alter or abolish it, and to institute new government, laying its foundation on such principles, and organizing its powers in such form, as to them shall seem most likely to effect their safety and happiness." --Thomas Jefferson: Declaration of Independence, 1776. ME 1:29, Papers 1:315
• "We think experience has proved it safer for the mass of individuals composing the society to reserve to themselves personally the exercise of all rightful powers to which they are competent and to delegate those to which they are not competent to deputies named and removable for unfaithful conduct by themselves immediately." --Thomas Jefferson to Pierre Samuel Dupont de Nemours, 1816. ME 14:487