Here today, gone tomorrow saying adjective phrase informal
I know your feelings for me are here today, gone tomorrow.
I need to buy this table right now because the sale price is here today, gone tomorrow.
There are so many new technology companies which are here today, gone tomorrow.
This idiom derived from to the short length of the human lifespan. It was used for the first time in 1549 in John Calvin’s Life and Conversion of a Christian Man.
To be thankful or grateful for one's good luck usually while avoiding a bad situation
You should count your lucky stars as you managed to avoid that violent car accident.