Do you check bobbin tension each time?

[Brenda Gagnon]

I rent a Millie at my LQS. I measure the bobbin tension for every new bobbin before I use.  They are prewound.  It’s crazy how bobbins out of same package vary so much in tension.  
 

but even when I make sure I have the correct tension the quality of the quilting on the back of quilt can vary greatly.  It’s difficult to check the back of the quilt while quilting.  
 

what do others do. Any suggestions. 

[Plumpurple]

Hi, I have used the prewounds and mostly like the magna glide BUT I do have better stitching when winding my own bobbins.  Have you tried winding your own or would that be an option for you? 
Sharon