Hard to say, there are obvious factors that make this question too varying to answer. For instance genetics, dose, frequency of use and past use of similar medications (opiates) all play a role in this. Tramadol is even more difficult to judge because it is quite different from the majority of opiate painkillers out there. With it's SNRI properties and a weak, selective opiate antagonist effect it tends to be a medication that has a more variable effect on it's users. Just read around on reports of people who have used it, you will find many who thought it was useless/weak and others who loved it.
I'm saying with most opiates you start to get dependent after 3 days of use, is it the same with tramadol or is it longer?
The best answer can can give is once you start to notice the dose you are taking is not working as well anymore. This typically doesn't take long, 2-3 weeks maybe, depending on frequency of use. This means your body is developing a tolerance to it and therefore is developing physical dependence to the medication. Mental addiction can start from the first time you take the medication and gets worse from there.
You are not physically dependent after three days of daily use. It takes a few months of daily use before you have a physical dependence. Sure if you quit after a few days you'll have a bit of diarrhea, but that's not a physical dependence. I'm talking restless legs, insomnia, vomiting, etc. It'll take at least a month of daily use before you've become physically dependent.
I believe it was in Junkie that Burroughs commented on this, saying something to the effect of 'it'll take you six months to a year to get your first habit, the next time it'll take a week'
I'm sure I've mutilated that quote, but he's right. The first time takes a long time, I was on methadone 60mg per day for six months and I quit cold turkey. It was on the third day I discovered what restless legs felt like. That was the extent of it though. I got back on it after a month's hiatus, and after 18 more months things were very different.