how long should i wait to text my ex bf?

so yesturday i decided to text my ex bf. he just got out of the army for good and starting college next month (actually going to the one i went to). after our break up in january 2009 we hardly spoke to each other. so when i contacted him, he actually answered me immediately. 20 mins after the text he called me and we talked. it was a very good conversation and he told me on the end "it was nice talking you." when should i contact him again? or should i wait for him to make the effort? when we were still together he always texted me first. thanks for your help.