That’s how long your thesis will be finished.
Once it’s done, it’s done.
Maybe it will be a physical book on a shelf in the library or a file downloaded by researchers. It could be appreciated for many years to come.
Perhaps it will only be looked at by a few – and perhaps, like me, you wonder who else your thesis is for…
Whatever the case, if it’s going to be finished forever, make it as good as you can.
Do your best when writing it and then listen to the suggestions and requests of your examiners. Corrections are the most likely outcome for the viva because writing is hard. After the viva you have one final chance to make any sensible, realistic changes to your thesis.
Because then it will be done. Forever.