When I was pregnant, I kept saying that pregnancy was lasting 9 months so we can enjoy sales !
I bought gender neutral stuff even when they told me it was a girl because I thought people would offer us a whole bunch of pink stuff already (which was the case). Whenever there was a sale, I would buy some onesies, socks, receiving blankets, etc.
I bought cloth diapers on the Kawaii diaper website, I was 3 months pregnant ! They were on sale (as they are now by the way) ;) .
I bought my changing table / clothing storage unit very early on and I did not even have the baby bedroom done. I just happened to pass by Ikea :p
The crib, we got it really late, I gave birth just 3 weeks after we received it, and I was pregnant for 42 weeks and 10 days...
It all depends on your financial means, the space you have to put that stuff on hold, who you think will give/offer you baby items and the opportunities you are faced with.
Best of luck on your pregnancy !