1. There is no "higher viscosity 5w30" oil. 5w30 is the viscosity.
2. In modern engines, you NEVER want to move to higher viscosity oil, e.g. 10w40, unless you know what the problem is. Thicker oils will cause more wear on the engine over time. Engines are DESIGNED for a specific weight of oil.
3. If you understand oil technology, you'd understand that in a warm climate, there is absolutely no difference between 5w and 10w oil, so moving from one to the other is neither a smart or dumb idea -- it's just an option. What happens is that when the engine is cold oil thickens. So if you live in cold weather, there is less friction to start your car with a lower weight oil. However, as the engine warms up, even in cold weather, the viscosity of both 5w30 and 10w30 will move to the second number "30".
In the olden days, when most production engines (not racing engines), had lower tolerances, there was more ring wear. Rings would wear out faster. When the car got significantly older, we used to put in a thicker oil. If the car was really old and we saw blow-by, we might even put in 50 weight oil so we wouldn't have to do a ring job. Things are different now and in modern engines, you should almost never do that. You have to move on from old myths as science and manufacturing progresses.
Oils today have advanced significantly especially with full synthetic oils. They will lubricate and protect your engine better than any oils in the past and should almost never be put in with higher viscosities. They have additives and most actually have a lifespan in excess of 10,000 miles. However, manufacturers are fairly conservative in their warranty recommendations and go to significantly less time. In our case, that's 6,000 miles for an SX and 7500 miles for the EX and LX models. Personally, I use the highest technology, full synthetic oil, just because I'm somewhat of a geek. If the warranty allowed it, I would personally go the full 10,000 miles as the scientific testing is quite good and I live by science and not old myths. I've been following the science and manufacturer's maintenance schedule for the past couple of decades and none of my cars have shown any significant engine wear and I've had absolutely no engine problems. To be honest, now that I'm very old and retired, I don't drive as much and actually don't even change my oil yearly even though it is recommended in the manual. Full synthetics don't degrade over time the same way the older oils do, and since I only use full synthetics, I don't worry about the time parameters. Again, I've never had any engine problems since the 1980's, and that was with a BMW 7 series.