I had a thread on this subject recently.
I had a lousy signal on some channels and was advised to retune.
I ended up losing many channels and had to wait until a day when the signal was strong to retrieve them.
Having got them back I left well alone and certainly don't intend 'to re-tune from time to time '.
I suppose I shall have to take a risk around 30 Sept but I expect it will not be straightforward.
And they call this progress!