Back up your data, then do a fresh reinstall of Windows 10, you will see the difference, nothing to lose anyway if your thinking of replacing it 

https://www.youtube.com/watch?v=F8nUrt18Okk&ab_channel=BigIrisProductions 

Note: One hardware upgrade that can breath new life in an old laptop is to replace the old HDD drive with a new SDD drive (also do a fresh reinstall of windows)

Higher end ones should last a bit longer. I have a low end laptop thats on its last legs ( 3.5yrs at £650) and a medium gaming PC thats still going strong ( 6 years still running at £1.500).

Like Yuri said, check the ventilation of the Laptop.

Also, give a look over your laptop's drives and also check to see if you're behind on any sort of updates.

If you're going to defrag any drives the laptop has, make sure they are HDD and not SSD, because you absolutely do not want to defrag an SSD, as that will shorten it's lifespan.

Here's a vid on trimming Windows fat:
https://www.youtube.com/watch?v=jCB1a1hokwg

Lower RAM usage and improve latency:
https://www.youtube.com/watch?v=Hhm56dBvtTQ

How to unlock Windows 10 ultimate performance mode:
https://www.youtube.com/watch?v=jlIC5kGFneA

Fix high RAM usage with Standby list cleaner (Also helps with latency):
https://www.youtube.com/watch?v=zXuOaOkVz8M&t

If you want to see what your drives read/write, you can use this guide, but I would not suggest using this for defragging an SSD:
https://www.youtube.com/watch?v=q-2cQL-Q4IM

Also, as a general tip, bring up your task manager and select the startup tab. Make sure you've only got the basics running at startup (Like Windows defender, but no clients like Steam, as you can start them at any time you want).

I tend to get a new laptop every 4-5 years, but the old ones are still useable for a long time after at least for simple tasks like browsing.

First laptop was £800 bought in early 2005, Packard-Bell IIRC, Windows XP, I still have it somewhere but suspect it wouldn't boot anymore as it must have been 10 years since I turned it on.

Second laptop was a Dell, whatever the basic 15.6" model was, I think about £360, bought in late-2009. Was originally on Vista but had a friend install W7Pro on it before I started using it properly. Developed a strange issue after about 4y where sound would randomly stutter (think short-sharp modem-like noises happening in the middle of watching a video). Never really figured it out however the laptop is still working as I have it at my workplace, "upgraded" to W10 2-3 years back, but it no longer charges and struggles with low RAM (making routes with Bing or Google maps for instance will slow it to a crawl)... For over 11 years old though I can't complain.

Third laptop was a Samsung, £500 in late 2012, W7 Home. Started gaming a bit more on PC with this one, but mostly older games as it didn't have a dedicated graphics card. Tomb Raider was probably the only game I played on it that didn't release before the laptop was built. It got hot in the summer though if I spent too long gaming, it still works fine for my parents though they only use it lightly for browsing.

Upgraded to a custom build in late 2015 (£700) to play more games, currently typing on it though it is a little worse for wear. I had the screen replaced last year (additional £100) and recently some of the keys need an extra hard press to work... then again I have used it far more than previous laptops, with a lot more gaming & a lot more hours video streaming so im not surprised it has taken a beating. Software wise though it's still fine, no problems with slowdown or anything, but I will probably start lookign for an upgrade soon.

Your experience seems consistent with my own.
I picked up a cheap laptop 2009 before upgrading to a good one 2012. The cheap laptop died 2013, while the good one died 2018.
Both laptops gradually got slower over time, while the good one started cracking and falling apart towards the end of it's life as a result of some screws being missing.

I decided to boot my better laptop up on a whim 2 years later (2020)) to see if I could get it working, but within 10 seconds the charger caught fire and melted, this was probably due to the laptop fan being able to blow heat directly on to the charger, which was only possible thanks to parts of the laptop exterior cracking and breaking off. The laptop was a lost cause.

Depends, many people have older ThinkPads still running. I myself am writing this on a laptop from 2012 with no problems. My parents use their 2006 laptop daily as a business machine.

It depends on the hardware in the Laptop. And if the <$1000 price tag of yours is any indication, this probably means a 2c4t CPU with low clock speeds and potentially slow and small memory, either of which is woefully inadequate these days, but if all comes together is slows to a crawl now. Speaking of which, can you tell us what you have in your laptop?

On a modern laptop these days with a Renoir/Cezanne Ryzen 5 or 7 or on the Intel side a Comet Lake with 6 or 8 cores or, with reservations since they only have 4 cores so far, a Tiger Lake, the CPU should be able to hold out longer and not get squashed as fast. It also helps that memory has evolved quite a bit since then (most laptops in 2015 still came with even by DDR3 standards slow-clocking DDR3L) and models with 16 or more GB of RAM are getting easier to find than models with 8GB or more back then.

As for the supposed replacement, what is your usage scenario? Do you need a slim, small and light model or can it be a bit bigger and heavier? Do you need or want the numblock or other extras like an RGB keyboard, a convertible build, a large hard drive/internal storage? And what would be your budget for the laptop?

I was actually thinking about this while using my switch. Browsing the E-store is unbelievably laggy. I only bought the damn thing last year....

Honestly it's not to have a go at the switch, but tech itself has an unbelievably short lifespan. It's actually depressing....

Depends on the built quality I suppose.

My old personal HP laptop is on year 8 and still going. It's a little slow (even with SSD installed a few years ago) but still usable for most everyday tasks.

My work Macbook Air is going on year 6, still strong though it chokes on rare occasion.

I bought a Macbook Pro a year ago for personal use after seeing how good my work Mac has been even after all those years.

I'm with these guys. A laptop vacuum/air blower is a worthy investment for so long as you plan to ever own PC or laptop hardware; good for several of your consoles as well.

I've been using the same laptop since late 2012, and outside of an HDD that's slower than molasses, it's still going fine and suiting my daily needs (I don't game on it at all). Every few weeks, I pull out the vac and clean the dust buildup. This massively improves its performance and ability to handle temperature, especially in the warmer part of the year.

Definitely start there, because it's the cheapest and simplest step toward improvement, and like I said, it's something that you should always be doing as long as you use hardware. If getting a dedicated computer vac isn't on the cards right now, then you can get canned air much cheaper.

I'd also follow Player2's advice about using an application that monitors CPU temperature. I personally use CoreTemp, and have it set to warn me when it reaches a certain threshold, and put the laptop to sleep if I don't opt out after half a minute. This can save your hardware. And if the laptop doesn't have a 1080p screen, adjust your video settings on sites so that you're not needlessly working your hardware to display higher resolutions.