However, I advise you keep doing shahada each day for the following reasons:
A) So that when death comes to you, you have practiced your tongue to say it so often that--Insha'Allah--you will be able to say it in your deathbed. You repeat at your deathbed what you say most often, or listen too or love, etc. So if you keep the love of saying shahada in your heart, have your ears hear it and your tongue utter it all the time...that--by the will of Allah alone--you will say it in your deathbed.
B) You may have an intentional thought without knowing it or uttered something that you believe doesn't take you out of fold of Islam, but in fact it does...when you keep saying shahada you will enter Islam again and when you pray it is accepted.
C) Saying Shahada all the time will increase your reward. There is no harm in saying it a thousand times a day or even saying La-illah-ilalllah as form of thikr and obtaining reward. Make your tongue light in saying it. Remember trees, rocks, animals even virus cells says shahada everyday. Why don't you?