My wife works in a lab, has a masters in biology and I'm decently scientifically literate and we had a hard time being confident that we were reading the paper strip correctly by ourselves.

Is it a faint line? How strong does it need to be?

Is that a line or is it a smudge?

Did we wait long enough?

Well these online instructions are for a previous model, are they still valid?

It's not easy. But having a calibrated machine tell you "pregnant" or "not pregnant" give a lot more confidence about scheduling a follow-up test with the doctor