I have this small memorial section left side is my mother and sister in law and the right are my maternal and paternal…

I have this small memorial section left side is my mother and sister in law and the right are my maternal and paternal grandparents. Every time I light a candle for them no matter where I have them placed, my in-laws candle always burns out the fastest. Same candle, same candle holder, I even light my grandparents candle first.