When should I take a pregnancy test

Annette
So yesterday and today I've had some spotting. I'm hoping it's implantation bleeding. About how long should I wait from when the spotting stops to take a pregnancy test?
Also could the spotting happen on and off and still be implantation bleeding? Late last night and early this morning I had no spotting and I'm just wondering if implantation bleeding would be consistent or on and off. Sorry if this sounds like a dumb question, but I've never been through this before.