Unless I don't age or die while time is frozen, I'm not using it.

If I DON'T age or die, I'd go around collecting incriminating evidence of corrupt people in power and get it into the hands of people I know could and would use it well Better world for everyone means better world for me. I'd also sleep. A LOT. I'd also steal garden supplies. Only a little unethical as far as stealing goes and on the upside, it would mean I wouldn't have to steal anything else, I'd have a sustainable food supply. I would also gamble a lot. Instead of going myself (so I wouldn't visibly teleport from one posture or facial expression to another), I'd have a partner go in and play poker, and split the earnings with them.

Sure, I could just cut out the middle man and steal the stuff I'd want but I don't want to steal or commit crimes where possible. I'd only steal garden supplies because they're cheap, replaceable, I'd only have to do it once and the payoff would be free food (or at least ludicrously inexpensive food) basically forever.

If I decide to be particularly helpful, I'd demonstrate my time stopping power to the world and ask how I could use it to solve the world's biggest problems. I'd also state, for the record, that any kidnapping or murder attempts on me or loved ones for any reason will result in me removing the leaders of the country responsible (and I WOULD find out who. being able to stop time means that any spy agency on the planet has a vested interest in earning my cooperation) from power by any means I see fit or utterly decimating the country as a whole (which I could definitely do with functionally infinite time, patience and no one and nothing to stand in my way). I'd make it clear that while retribution would be swift and devastating, cooperation would be rewarded. Not always, any place with a despotic leader or government gets a solid NO from me but as long as you leave me alone, I leave you alone.

Anyway, having told the world of my ability to stop time, all manner of organizations would be vying for use of my power from governments to scientists to corporations. With the vast array of resources at my disposal I'd work to solve the immediate threats that plague humanity. Global warming, poverty, corruption, illness, starvation. To save time, i'd have these groups attend meetings with lists of requests for me to fulfill so I don't have to spend as much time talking with them in unfrozen time, only unfreezing time for clarifying questions to be answered, and I could simply read what I needed to do and do it at my leisure.

I think about what I'd do if I could stop time a lot, these are some of the things I've considered. If you can stop time and don't age or die of age while time is stopped, you basically rule the world by default. Who can stop you? Who can even IMPEDE you for any amount of time. It might take a bit to get what you're after but it becomes inevitable when you never have to stop trying. EVENTUALLY you'll succeed. The only risk you face is assassination attempts while time is unfrozen but you can mitigate that by controlling the conditions for being in public and by freezing and unfreezing time at random. If a sniper can't pin you down or you otherwise never let yourself be vulnerable (by, say only sleeping, using the bathroom or eating in frozen time), you're untouchable.

Sorry for the length. TLDR: What would I do if I could stop time? Conquer the planet. And start a garden.