I've got an Irish stout that has been going for about three weeks in primary. It had a really slow start. Nothing for 48 hours really, then a crazy period for about three or 4 days. Then a bubble every 30 seconds or so since. I haven't messed with it or taken any hydro readings yet. Might let it go 4 weeks total then bottle it.
It all just depends on temps, yeast type, fermentable sugars, etc. Who cares, let it do its thing in its own time. Always give 3 to 4 weeks to condition, bottle and enjoy it in another 3 to 4 weeks.
Most stouts tend to be in the 4.5-6.5 range. I prefer the ones that aren't super HG but that's just me. Good luck!