Like Diamc said, it's always best to have the UVB bulb. But if your dragon is outside for at least 45 min. - hour every day, or a couple of hours every other day, he should be fine. I've raised lots of them that way, and the important thing is to also be sure that you still have a hot basking spot in the tank when you bring him back in that he can choose to bask under. But he should be fine until you get the money for the bulb as long as he eats well and you still use calcium [ without D3 ]
Oh his tank has 2 basking spots and I nice cool hide under fake plants. Outside time in a pen as well
He's 2 yrs old and always I have used calcium with d3 mix. Why should I stop?
He gets it once or twice a week, he is very healthy maybe a bit overweight but that's it
If he goes outside on a regular basis, he still needs calcium, but the sun provides the D3. You might use calcium with D3 once a week, and calcium without D3 once a week. You just want to be careful because too much D3 can be toxic.