The chimney at your home is in probably the most exposed position: open to the driving rain, wind and snow.It’s important to keep it in good condition.
Keep the mortar pointing between the bricks sound. If it erodes the brickwork loosens and may become unsafe. Check the flashings around the base of the stack where it projects above the roof line are secure. If they work loose rainwater can penetrate into the structure damaging roof timbers, and ceiling /wall plaster and decorative finishes.
Whilst your builder or roofer is up there ask them to check any pots and flue terminals are firmly bedded in a mortar base (“flaunching”) and that your tv aerial and/or satellite dish are securely fixed.
If anything falls off a chimney it could damage the roof, the car parked on your drive, you or a passerby!