Clutch or Syncros

[kcty]

Hi everyone... I had a question about my Yaris and thought I'd pick your brains.

I have a 2007 Yaris Sedan with a manual transmission. I've owned it since day one (had 20 miles on it), and it now has 235,000 miles on it (378,000 km). I've not had to do much to it, and I've been very happy with it. Basically I've just done standard maintenance and have had recall work done to it. In the last few months, I've had an issue develop where the car grinds when putting it in gear once in a while. It almost always grinds if I try to put it in 1st when the car is rolling at all, so I try not to do that. However, if I come to a totally complete stop, most of the time it drops right into 1st, but once it a while still grinds. 1st to 2nd will also sometimes grid, but most of the time it's fine. Also, once in a while it grinds going into reverse. Sometimes the grids sound very slow, like going into 1st, I can hear just a few teeth before it goes in, and other times it's full-on grinds.

In all honesty, I'm a little hard on my clutch, so my first thought is the clutch. However, I've also heard of some issues with the syncros, and some people on here are getting over 300,000 miles before the clutch needs to be changed. So, I wanted to get your thoughts on it. While I have no problems changing out the clutch, I'd hate to do it, if that's not the issue. As for the transmission, I use quality transmission fluid in it when I change it. It's currently running Red Line, but has run Royal Purple as well. I wasn't fond of the way the Royal Purple felt when shifting, so I only used it once.

Any thoughts? Clutch, syncros, or something else?