Someone once asked me this question: is it better to open products or keep them sealed? The answer is a bit complex, but let me explain how I feel about this.
First, opening products will almost always make you lose money; the total cost of the cards you pull will be lower than what the sealed product is worth. There's some exceptions, such as products with a single expensive chase card(looking at you, Silver Tempest). But largely, opening is not a good investment strategy.
That being said, you also need to know what Pokémon products will increase in value over time. Some Pokémon products hardly increase at all even after many years(look at you, Steam Siege). Also, even if the overall value of a product is high, there's no guarantee that it will ever sell for market value. However, if you do manage to invest in a winner, there's definitely money to be made(looking at you, Evolving Skies & Brilliant Stars).
But this all leads us back to our genesis: why do we get in the hobby in the first place? Personally, the only sealed products I would invest in are Elite Trainer Boxes, mostly because some of them look absurdly cool on the shelf. But investing in a booster box to keep sealed? I don't have the wherewithal to resist the temptation of opening it. I got into the hobby to collect cards, not have a bunch of boxes sitting around for 10 years before I think about selling. You're better off studying and learning the stock market.
Think about why you're getting into the hobby. Is it to collect or make money? Personally, I wanted to do both. That's why I started a hobby shop. What is cool and what is not cool to you?
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