Let's pretend you were just elected to office. You have become a town councilman or a county legislator or you are on your way to Congress. You have a lot on your plate so you can't be blamed for not making your social media profiles your highest priority. However, there is one mistake you could make that would almost guarantee that any following you attract while in office is lost the day you leave your position; you could name your account using your new official title.
What's In A Name?
Everything. The answer is everything.
When you name an account "Congresswoman X" or "Senator Y" you are sending the message that the account in question is an official government account. By holding out an account as officially belonging to the government you are making it easier for anyone who comes after you to argue that the page is government property and therefore should be turned back over to the said government. Once that happens whomever replaced you, likely a political rival, could delete the account all together (although I would argue that would be a violation of record retention laws) or change the name to reflect their own ideas or brand.
Had your account been named purely after yourself it would be far more difficult for government actors to argue that it is in some way the intellectual property of the government. The same is true for how and by whom the page was created; if it was created by you or a volunteer on personal time the page is likely your own but if it was created on a government machine by a government employee the argument can be made that it belongs to the government.
Real World Examples
The two most obvious examples of this are the official government accounts of the last two Presidents of the United States of America; Barrack Obama and Donald Trump. Both Obama and Trump had governmental Twitter accounts; @POTUS44 and @POTUS45, and both lost access to their accounts once they left office. Both are now maintained by the National Archives and Records Administration.
The idea that official accounts belong to the government is not limited to Presidents. Former Vice President Mike Pence also had his Vice Presidential Twitter account taken when he left office. Further, new rules for House members passed in recent years clearly demarcate between government activities and personal activities on social media by banning the posting of pictures and photos from ones office in Congress on members personal social media account but not prohibiting sharing the exact same content on an account that has been designated as the account of the office itself.
How This Would Play Out
Let's consider a hypothetical. You have been in a town councilman position for 8 years and built up a healthy Twitter following with an account titled "CouncilmanJohnSmith". You have set your sights on higher office so you decide not to seek re-election. Much to your surprise your hand picked successor is defeated by a member of the opposing party. You think "well, at least I didn't lose" and you prepare to leave office and take your Twitter account with you. You even change the name to reflect your new civilian status as "CivilianJohnSmith".
Assuming your replacement wants access to your account, or at least to deny you access to it, the first thing they will do is serve you with a cease and desist letter. You are in possession of government property, the letter will warn, and a refusal to transfer the ownership and control of these assets may be a violation of the Government's Code of Ethics, the Government's intellectual property rights under the Copy Right Act 17 U.S.C. § 101 governing work made for hire within the scope of one’s employment, or even the Penal Law.
Next you could be served with an Order to Show cause demanding the Court order you turn over the account or a full blown lawsuit alleging damages.
Worst still, your opponent may even go to the press to get some publicity for themselves. It is not hard to imagine the spin; "the previous owner of my office used government resources to build and maintain their account, held it out as government property, and is not stealing it for their own benefit."
How to Protect Yourself
There are two options for protecting yourself from the above scenario. Firstly, you can simply create two different accounts; one governmental and one personal. You will still lose access to the governmental account when you leave office but at least you have one asset that is yours.
The better strategy and the one I suggest is you create an account for just you. No title. No campaign. Just your name. This will give you the wiggle room to use the account for both governmental and political initiatives. The only limitation would be that you cannot use governmental staff or governmental machines to post political content. The reverse would be permissible but it may serve to just muddy the waters so it should be avoided.
Losing access to social media is tantamount to losing access to a large section of any constituency. Failure to understand the pitfalls with government created accounts leaves an individual open to many easily avoidable situations.