I have found that paper strips are truly unreliable. While I concur that there are plenty of unreliable or short-lived pH meters out there, most will provide a reasonable assessment of pH after they have been calibrated and have proven their stability with the trials that AJ recommends.
Just because you obtained a result with paper strips, it doesn't mean its accurate or reliable.
Just because you obtained a result with paper strips, it doesn't mean its accurate or reliable.