沿用 (yán yòng): to continue to use (old methods); to apply as before; according to usage

For decades, this small restaurant has kept using its family's traditional recipe to make soup, and the taste has never changed.

Although the company got a new boss, the original attendance system has still been kept in use.

To save money, when renovating his home he reused the floor and the doors and windows from the old house.

This textbook continues to use the structure from ten years ago; it has only replaced the examples inside with new ones.

If we keep using the old methods, it will be very difficult for us to increase production in a short time.