Everybody loves a successful startup, but even the most successful startups generally overcome plenty of mistakes before they become successful. Unfortunately, for many young companies that don’t win in the marketplace, failure is the product of fatal mistakes.

Like most things in life, mistakes aren’t created equal, and when it comes to the mistakes that can really hurt a young startup, technology mistakes can be particularly pernicious.

Here are several of the biggest technology mistakes startups make and how they can be avoided.

Being seduced by premature optimization.

As a founder or employee of a startup, it’s healthy to be optimistic about its prospects for success. After all, if you don’t believe what you’re working on has a shot, you probably should be looking for a different opportunity.

But overoptimism can lead to a harmful mistake: premature optimization. Yes, performance and scalability are important, but when your company pulls out the big guns in the name of optimizing performance and scalability before it has real traction, valuable resources (namely time and money) can be rapidly depleted unnecessarily.

How to Avoid

Remember that when it comes to optimization, chances are you’ll make incorrect assumptions about usage and growth patterns anyway. So focus on building something that works and is maintainable, but don’t pretend that you’ll have 1m new users overnight.

Picking cool over proven.

There’s arguably never been a more exciting time to launch a startup. One of the biggest reasons: the plethora of new technologies, many open-sourced, which enable even the smallest startups to do things even the largest startups would have found challenging a decade ago.

From the sexiest NoSQL solutions to useful tools open sourced by companies like Facebook and Twitter, startups have no shortage of cool toys to play with. That, of course, doesn’t mean they should. Picking the latest and greatest over the more mature and mundane can create more excitement, particularly for developers, but it’s also a good way to make fatal architectural decisions.

How to Avoid

Respect your developers, but keep in mind that developers have plenty of reasons to make technology decisions that work against the company’s interests. That’s why it’s so important to make sure key technology decisions are being made by someone with real-world architectural experience.

Not investing enough in UI/UX.

Thanks to the aforementioned new technologies and general decline in the cost of hardware and software, it’s easy for companies to focus on the backend. After all, many founders believe that great systems can become significant competitive advantages.

But great products are usable products, which is why companies that fail to invest in frontend development are liable to see their great backends go unused.

How to Avoid

Recognize that appearances matter with products, so budget to bring a UI/UX person on early in your startup’s development.

Hiring too many developers too fast.

At many startups, developers are treated like rockstars and you can never have too many. There are a variety of reasons a company will buy into this notion. One of the most common, of course, is that, in theory, more developers equals more code.

But growth in developers doesn’t necessarily lead to greater productivity, particularly at early-stage startups just building out a product. In fact, in many cases, more chefs in the kitchen will not only not lead to things getting done more quickly, it will lead to significant problems with the quality of a company’s code base down the road.

How to Avoid

If your startup hasn’t raised millions of dollars in funding, it’s generally easy to avoid this mistake; you simply won’t have the funds to go on a hiring spree. If you’re raising money, think long and hard about what you promise investors. In short, be careful about promising to grow your development team rapidly simply because that’s what they may want to hear.