Jeans denim 80/12 sewing machine needles.

Sewing machine needles by Schmetz are wellknown and of excellent quality
Use jeans sewing machine needles for sewing denim. Also suitable for Canvas, twill, tarpaulin and oilskin

If you are sewing jersey, denim, stretch fabric, leather or other special fabrics choose the needle to fit your fabric. The result will be better. Also check the needles NM, thin fabric, thin needle, thicker fabric, thicker needle...
 

Is choosing difficult?
In this PDF we have explained the combination of fabric, threads and needles: 
Thread and needles user table

TIP: a needle kan work for 8 hours, afterward it is blunt and needs replacing.

That does not mean that you have to exchange the needle after one day. Look at it this way: if you should push the pedal and keep it sewing for 8 hours straight the needle is blunt 
Easiest way is to put a new needle in the machine when starting a new project...