Are you getting holes in the same place ? Check your rim tape if the hole in on the inside of the tube. Check your tire for objects embedded in the tread. Holes on both sides of the tube at the same time (snake bike) is caused by under inflation and hitting pot holes, curbs, rocks, etc. If you run over glass stop and wipe off the tire with a gloved hand. Same thing if you pick something up on your tire and you can hear it hit the pavement as the tire rotates. Keep an eye on your tire pressure and watch where you go.