If you planning to reuse balloons, I would really recommend to inflate the balloon prior reuse with air to inspect for any damages. It would be a waste of Helium to discover punctures right before flight.
Also you should handle the balloon with care. Inflate and deflate on clean surface, wear gloves, cover piercings and jewelry.
If you are planning regular tethered flights, you should consider to invest in a durable balloon than a weather balloon. There are balloons used for advertising which have thicker canopy and ideal for reusable tethered application. Or you can try zero pressure foil balloon configurations. They are not stretch so maybe have less stress on the canopy.