For the Braun Series 9 Pro 9420s, you'll want to replace the shaving head roughly every 18 months. This recommendation comes from the manufacturer to help keep your shaver working at its best. They suggest that after 18 months, the cutting elements, including the ProLift trimmer, can start to lose their sharpness, which might affect your shave quality.

Why the 18-month mark? With regular use, the blades will naturally get dull and the cutting elements can wear down. By swapping out the shaving head as suggested, you’ll keep your shaver’s performance top-notch and enjoy a close, comfy shave every time.

As for the battery, the Braun Series 9 Pro 9420s uses a lithium-ion battery designed to last and hold a charge for up to 6 weeks. The manufacturer doesn’t expect you’ll need to replace it often, but if you notice it's not holding charge as well after a while, a new battery might be necessary.

So, to keep your shaver in great shape, plan on changing the shaving head about every 18 months and just keep an eye on the battery’s performance.

Regular maintenance will go a long way in maintaining the quality and reliability of your Braun Series 9 Pro 9420s.

If you're thinking about switching from a manual razor to an electric one, the Braun Series 9 Pro 9420s has some cool features that might catch your interest. This shaver has a built-in ProLift trimmer designed to handle both short stubble and longer hair.

According to the manufacturer, it's particularly handy for trimming things like sideburns and necklines, and our research backs that up—people have found it really effective for those tricky spots that can be annoying to get with a manual razor. The convenience factor is a big plus, too; it could save you some time and effort in your daily routine.

Another thing to consider is the shaver's head, which has five shaving elements (including the ProLift trimmer). These work together to lift and cut hairs more efficiently, making your shave smoother.

The manufacturer claims this design offers a closer and gentler shave compared to traditional razors, and our research shows that it’s also great for detailed work on mustaches and cheek lines.

Worried about skin irritation? The Braun Series 9 Pro 9420s aims to be gentle on your skin, which could make for a more comfortable shave. Plus, since it's a Wet & Dry shaver, you can use it with shaving foam or even in the shower, whichever you prefer.

One more thing: unlike manual razors, you won't need to replace the blades as often. That could save you some money over time.

So, if you’re after a shaver that mixes precise trimming with a close shave, the Braun Series 9 Pro 9420s might be a solid option.

Yep, you can definitely use the Braun Series 9 Pro 9420s in the shower. The manufacturer describes it as a Wet & Dry shaver, so it works both for wet and dry shaving. This means you can use it in the shower or with shaving foam and gel, depending on what you like. It's pretty handy if shower shaving is your thing.

Plus, since it's fully waterproof, you can rinse it under the tap without worrying about any damage. That's great for keeping it clean and hygienic after every use.

And if you travel a lot, the PowerCase can be really useful. The manufacturer says it gives you 50% more battery life, and our research found it can last up to 6 weeks on a charge. So, no stress about constantly needing a power outlet while you're on the go.

So, yeah, the Braun Series 9 Pro 9420s is perfect for wet shaving, including shower use, and it’s easy to clean.

Add in the extended battery life from the PowerCase, and it’s a solid pick whether you’re at home or traveling.