What is the ruling on invoking blessings upon the Prophet when selling and when wanting to recall something forgotten?

Allah Almighty and the Chosen One, peace be upon him, commanded us to send blessings upon him. This is an absolute act of worship, except in specific instances. Designating specific times or places for sending blessings upon the Prophet, peace be upon him, that have not been prescribed by the Shariah, such as sending blessings upon him during buying, selling, or when forgetting something, is considered an innovation (bid'ah). This might transform it from an act of worship into a mere slogan or ordinary speech.