We have a cream carpet in our living room which was here 7 years ago when we moved in. We had it cleaned and it looked ok which was a relief as we couldn't afford a new one.
Fast forward to today and I have a 2yo dd and am expecting dc2 in September. The carpet has big grey blotches on it that only show up in certain light (I think this comes from wearing black socks) and when I lift the rug up it looks like we still have a rug down because the carpet is a different colour underneath 
I have a very very old vax which we use from time to time and seems to pick up loads of dirt but within a couple of days the marks are back in exactly the same place.
We can afford a new carpet now but with 2 small dc's my dh thinks its better to get a new carpet cleaner and buy a carpet when they're older (its a big room).
What would you recommend, a steam cleaner type, an upright vac or something else? 