First, remember that not everything that's labeled "ergonomic" is actually good for you. Some "ergonomic" products aren't an improvement on the basic models at all, just trying to get your money; some are good for some people/situations but not others. There's no single "ergonomic equipment" category with a single learning curve, and any study results that apply to some type of mice and keyboards won't apply to others.
The most important thing is paying attention to your body's signals. Especially any pain or aches, but smaller signals are important too - do you feel like you're twisting your hand in a weird way to reach a key? Do you feel like you're having to press the keys pretty hard? (The last one's definitely a good reason to get a lower-pressure keyboard - I don't think there can be any downside to those). Anything you notice, it's probably a good idea to fix. If everything seems fine, perhaps you won't have issues with the standard equipment, and you might be worse off with a keyboard shape you find uncomfortable.
If you do want to try something ergonomic, make sure to do some reading and research before buying - see which ergonomic ideas make sense to you, try things out if you can, and so on.
If you're not sure what you want, it can be a good idea to get a keyboard with a lot of adjustment options (tilt, split angle, tenting) - I have this one, and I really like the fact that I can change all the angles until I get something that actually fits me, rather than being stuck with a fixed shape.