Borrowed garments never fit well.

The image is of wearing another person’s clothes: they may serve a purpose, but they are unlikely to fit as comfortably as clothes chosen for oneself.

Figuratively, the proverb suggests that a borrowed solution or way of doing things may be a poor match for one’s own needs or circumstances.

Use it when someone adopts a solution, role, or approach from another person without considering whether it suits them. It can gently encourage choosing or adapting something for oneself instead.