Rechecking tests

Does anyone else take a test in the morning and keep it to check it later that day? Have you ever had a faint line when you checked it later on? If so, was it a true positive? I took a test this morning, the same brand of test I've taken plenty of times, (same tests we use at my job) when I checked this evening there was a faint but visible line. I'm not getting my hopes up but I've never seen lines show up on these tests if it wasn't positive. I'm going to recheck in the morning but jw other people's experiences.