Spotting

I've never been one to spot in between periods but the last 2 months I have on days 10-12 of my cycle. Last month, after spotting on days 11-12, my period was 4 days late. I'm now on day 10 of this cycle and I'm spotting. Any ideas on if this is good or bad? We've been ttc for 6 years and all tests have shown there are no problems.