When considering estimating a performance over 1 year, you should take into account:
1. Google’s algorithms are constantly changing; it doesn’t change overnight, but in a few years, things vary;
2. Competition changes, too; your competitors change from one point to the other;
3. Your goals change – if you target a keyword now, perhaps you will target a different one 6 months from now.
So, while some things in SEO remain intact, there still are some changes to be done.
