It is a long and ongoing series, but an incredibly rewarding one, in my opinion. Some of the best JRPGs I've ever played, even some of the weaker ones in the series.
Back when I started playing the series, the most recent title in the West was Cold Steel 4. From the first game up to that one is nine games. It took me almost exactly one year to the hour to finish the series up to that point:
Trails in the Sky FC prologue achievement:
Trails of Cold Steel IV true ending achievement:
This wasn't intentional, and I only noticed this when I finished CS4. I took very few breaks from the series during that time. I think the most I took was maybe two months between Trails in the Sky the Third and Trails from Zero because there wasn't an official localization of Zero and Azure at the time, and I had to get the fan localization going. I still remember being so into Azure that it only took me 10 days to beat it....taking about 110 hours all while still going to work, sleeping, doing my regular things.
I could sperg on for a long time about how much I love this series, but I'll stop for now by saying that it is an amazing series if you have the time to invest in it, even if slowly. I've been lagging on catching up with some of the recent games in the series, but I'm trying to finish a few games I'm playing right now and plan on getting back to