Kito and Abbey were trained when we got them, but Riley wasn't. We used a crate when we weren't home, and were very strict about getting him out every 2 hours, after he woke up, and after he ate.
We also kept a journal of all of his trips out, to get a better idea for how long he actually does wait, how many times he goes a day, and what times. It varies a little, but was very helpful.