Need hoof pics(see link below) if you'd like a critique. More info on diet, management etc would be helpful, to give you more.
As others have mentioned, good diet and *well balanced* nutrition is an important factor in hoof health. Applying topical will generally have no effect. As with our own hair & nails, the outer wall is already dead, so you can't improve it's health by painting it. The outer wall is also largely impermeable(if not cracked), and designed to be dry. An exception to topicals is if your horse is in a wet environment and you want to apply a sealer to prevent excess moisture getting in. But then, sealers aren't typically effective on the bearing, wearing surface of a horse's foot, and if the wall is whole, it won't be needed... Another reason to be cautious of topicals, especially if they're oil based or sealers, is if there is any infection present(very commonly is in cracks), it will seal it in & make for a nicer environment for growing the bugs.
Good, frequent farriery is vital too. Every horse is different and some can indeed go 6 weeks or even more between trims without issue, but they benefit from being done frequently enough to *keep* the hooves in good, functional shape, rather than allowing a lot of overgrowth before the farrier comes to 'correct' them. IMO most horses need doing more frequently than 6 weekly, so they don't overgrow & distort too much. It's important IMO for owners to do their own homework, as for one, unfortunately it appears to be a worldwide common thing that there are very much more average or bad farriers than there are good ones out there. If you have no idea whether your farrier's... helping or hindering, then you have nowhere to begin finding answers.