"Is the repair time-dependent or mileage-dependent?"
That is a Factory Recommended Mileage, based on Tests & Info the Factory has established. Following a Good Service Plan will usually make your Vehicle last longer.
Of course, there are those that will tell you that they never follow Factory Guidelines and have no problems.
"Should the repair be done now?"
Regardless of Mileage, the Belts, Oil, Coolant, Battery should be checked on a Regular Basis.
The Belt should be checked for wear, cracks, chips, etc.and Relaced if it shows any of those signs.
" the belts are squealing when the AC is turned on, right after the engine is started"
If the Belt "squeals" only when the A/C is turned ON, it probably is the Belt. Heat & Wear causes the Belt to stretch. When replacing the Belt, Clean ALL Pulleys, Check the Tensioner for proper Strength & Check Alignment of All Pulleys.
This is a PAY Site:
Your Deposit is Not Payment....Please Click the ACCEPT Button !
Feedback & / Or Bonus is appreciated...~*~Thank You!~*~
1 Other Expert Agrees with this!