Welcome to HCM.
If your prescriptions were for near vision, then they were right, as it is called Presbyopia
,Where in ,due to aging, the lens
inside our eyes loses its flexibility making it difficult to see the near objects. The treatment includes reading glasses,which has to be replaced once every 2yrs to reduce the eye strain
Since you are 53yrs,your ( March,July and Sep) changes could be due to early cataract
changes causing fluctuating powers. I suggest instead of having another consultation at this level, (instead of you getting more confused) wait for another 6 months ,get a dilated examination done and then decide how to go about it.Until then continue your latest glasses.
If your prescriptions are for distant vision, then it could be due to cataract changes which must be very early.
Please check your blood sugar level too as irregular levels can cause fluctuations too. Take care.