Gossamer,
Hello and welcome to the forum. As important as how often you water it is
how you water it. When you do water it, have you been watering it thoroughly or perhaps only providing a small amount of water? I ask because the shriveled leaves tend to indicate that you are not watering it adequately. When I water these I always saturate the soil.
Your plant looks to have been last re-potted some time ago since the soil seems somewhat compacted. When this occurs it can sometimes be difficult to water a plant to the core, which is always important.
This species,
Portulacaria afra can indeed go for extended periods without water but whenever I see shriveled leaves I know I have waited too long. FWIW I find Portulacaria to be far more tolerant of frequent watering than full sized Jades, especially during their active growth period. This is, of course, relative. Both species are succulents and require less frequent watering that many others.
The chopstick method will not be as useful to you as it would be for other species that should not be allowed to become too dry. This method, while largely used to prevent over watering, also aids in preventing under watering. This is much less of a concern for Portulacaria since they are not nearly as sensitive to drying out. In other words, you won't need the chopstick to tell you when to water since allowing it to dry down well won't hurt it.
My apologies for my ignorance in this regard. I had no idea it would be so detrimental to my post, and around my household we've been referring to it as another person. My post has now been edited to remove the offending language.
It's not offensive or detrimental, just one of those things that beginners often do that more experienced growers generally don't. Don't give it a second thought.
Norm