Thanks for your inquiry.
BMM150 x/y axes are based on Bosch Flip-Core technology and z axis is based on Hall Effect technology. There is no moving part inside BMM150 so the performance/stability will remain the same after 10 years. It will not degrade due to weather, temperature, etc.
BMM150 is not recommended for new design. Please consider new magnetometer BMM350. BMM350 datasheet is available online.