I used to think grout was grout, one tub of white stuff, smear it on, wipe it off, done. Then I regrouted a shower myself, used the cheapest sanded grout on the shelf, and watched it crack and stain within four months. What fixed it was learning that the gap between products in this category is enormous, and the cheap end just does not hold.
The honest limits first. No adhesive or grout is going to rescue a bad surface underneath it. If the wall or floor is uneven, damp, or moving even slightly, the best tile adhesive in the world will still let go eventually, and grout will crack along the same lines every time. This is also not the place to save money if you are tiling a shower or a kitchen backsplash that gets heat and steam daily, because the gap between a mediocre product and a good one shows up fast, usually within a year, usually at the worst possible seam. Trim has its own limit too, it hides a gap, it does not fix a bad cut, and if you are expecting it to disguise a wall that is out of square by half an inch, it will look like exactly that.
What separates the good from the disappointing comes down to a few things you can actually check before you buy. With adhesive, look at whether it is rated for the material and the location, a flexible or polymer modified formula for anything near water or heat, not a basic all purpose one. With grout, epoxy based versions cost more and are a pain to work with, but they do not stain, do not need sealing every year, and do not crumble at the edges after a few winters or a few hundred showers. Cheap grout looks fine on day one and starts going gray and pitted by month six. For trim, the difference is in the material and the finish, solid wood or a proper composite that will not swell if it gets damp, with a clean factory finish rather than a chalky paint job that chips the first time a vacuum bumps it. Joints matter more than people expect, a trim piece mitered badly will show a hairline gap that just gets wider as the house settles, especially after a move when everything shifts slightly on a new foundation.
This stuff suits every kind of home, rented or owned, because it is usually the cheapest fix with the biggest visible payoff, a tiled splashback, a finished skirting line, a floor that does not look unfinished at the edges. Older houses with uneven floors benefit most from flexible adhesive and a slightly wider grout line, which hides movement better than a tight one.
The detail I never get tired of is grout that stays the same color for years, no sealing, no scrubbing, just quietly doing its one job.