That is easy to answer with just a few questions.
How old are they? If they have been hanging in a sunny window for 20 years, they may have begun to disintegrate and may not withstand a cleaning.
Do you recognize the manufacturer? Some blinds purchased from big box retailers may be inexpensive when purchased, but do not hold up well over time. The strings and brackets wear out and may not be worth replacing if parts are difficult to find.
We can often restring the blind and get it working good as new, however, if the blind is not made of quality materials, the repair cost might out-weigh the replacement cost.
If the broken blind is one of many matching blinds, repairing might still make sense if the others are in good shape.
Our cleaning process removes most stains and odors and is a sound value if the blinds are in good repair, are made well and you like them. In that case, cleaning the blinds would be worth the investment.