I find that it makes lot of difference what I'm printing.

For ABS, I use kapton. I have the Matrix Precision bed, so I'm 8x8 and use this stuff. www.amazon.com/gp/product/B00UIAG970. I find that one sheet lasts me months.

For PLA, I use two strips of 4" blue tape - on top of the kapton - and then move my m212 up 100um.

For ninjaflex, I also use blue tape on top of the kapton