As most have already said, the desire and the urge has always been there, it was never all consuming, but it's something that's usually always in the background even when I'm being an adult. With where I'm at now, I probably wear and regress about 3-4 days a week, that's usually all that time will allow as I work and have school obligations to worry about. There are times however, where I have to forgo the desire to regress in order to focus on the task at hand, case in point, for the next 3 weeks I won't be wearing or regressing at all, I'm not at my apartment, I'm in another province working on a freelance contract. So, in general, the urge or the desire is usually always there, every day of the week, it's just not extreme in any capacity.
The desire has not become less frequent, but it has become standardized, I guess. Let's just say, the desire to regress use to be overwhelming back when I was a kid/teen figuring this stuff out, back when I didn't really have the resources or the space necessary to adequately explore. Now that I've been babying out multiple times a week for the last 8 years that I've been living on my own, the desire is largely second nature for me. I still have the desire to regress every week, but it's more of a natural thing now, I do it when the time is right and it always lifts my spirits and makes me feel whole
Last question is a bit difficult, but I'll give it a shot. For me, the urge has always been to regress, diapers are an accessory in that regard, they contribute to the realism, they aid in my regression. As my desires have become a bit more par for the course in my daily life, I guess you could say the urges have plateaued a bit, they've become more standard. So, yes, I still wear and regress, even though the urge is much more subdued/typical now, why? Because being a baby is a part of who I am, it makes me happy and it's a great stress relief