yep it's going to be a judgement call but I believe if you have good brakes after you swap the reservoirs and you take it for a ride and you still have good brakes, then you will always have the good brakes. I happen to have experienced this very situation in May of this year. I was checking my Healey over for the trip to the Smoky Mountains and I found the reservoir fittings leaking. Nothing I did would stop the leak so I bought a new reservoir. Popped it on, filled the can and when for a drive. Brakes worked perfectly. I drove it a few more times before I went to South Carolina. Down there I drove for 5 days and covered 1200 miles. Brakes still worked perfectly. Have been out many times since, including this evening for about 3 hours , have never yet bled the brakes. They work perfectly.