The best way to solve this problem is by installing a water flow gauge that will tell the plumber what the water flow rate is through this hot water circulation line and then adjusting flow to meet the minimum flow requirement and there by minimizing the erosion factor.
If you have additional pumps on the circulating hot water line, get an electrician to have these circulation pumps wired together and install an electric timer that can shut these pumps off for a period of 10 minutes out of each hour at the same time.
If you have a single pump, which is often the case, the electrician can tie in a programmable timer for this single pump.
A water flow gauge gives the plumber servicing an immediate tool in determining if the circulating pump is working properly thus saving trouble shutting time.
There is no accurate way to tell if a circulating pump is moving enough or too much water short of a water flow indicator.
A secondary benefit that results, if you have a thermostatic mixing valve, you can now determine if that thermostatic mixing is working properly.
These preventive maintenance steps will not eliminate hot water circulation line leak(s), however these timers will greatly reduce the erosion effect that is occurring in the copper pipes and thereby minimize the number of service calls required to fix these leaks.