Anyone with an electronic device should take steps in order to make it as private as possible. Even if you don't have anything to hide it is still your property and even if you are dead, no one have the right to violate your privacy. I work in IT and I know how easy it is to recover deleted files or even break into a computer - a password doesn't stop someone who knows what they are doing.
Things you can do that does not require much effort:
1: Encrypt your device. This can be done with for instance Windows Bitlocker or Apple FileVault. This makes the drive unreadable to anyone - even the police. A simple guide can be found in at this link
https://spreadprivacy.com/how-to-encrypt-devices. There are alternatives but I always recommend Bitlocker and FileVault for their simplicity, and the security is more than enough. I would also strongly recommend encrypting your phone as this is something people overlook. We carry a lot of information in our pocket which can be used to access other devices (passwords to accounts etc.).
2: Get a password manager. Many of us use the same password all over the internet. You can see why this is a pretty bad idea, once someone gets a hold of this one password they have access to all your accounts. Using a password manager (most browsers will have one) you can use new, strong passwords for each of your accounts without having to remember them all. The only password you really need to remember is for your browser account - this one should be changed regularly.
3: Make sure your deleted files are overwritten. A common misconception is that deleted files are wiped from your device. This is not the case as the file is only hidden from the user until a new file is written over it. This can take a long time - I have seen files from several years back stick around. There are multiple programs that can be used for this purpose. CCleaner is a good, free option which allows you to overwrite unused space from your hard drive. If your drive is encrypted (step 1) you don't really have to worry about this.
4: Start using a VPN. I won't go much into this but every site you visit will be able to see who you are without a VPN. Your IP-adress is like an address on a post card. With a VPN your IP will one that is used by thousands of users and all the data sent between you and the site is encrypted. Your internet provider will not be able to see what you are doing, except that you are connected to a VPN. People are ignorant when it comes to what they do online. Everything you do online gets logged in some way or another, so even if what you are doing is completely legal it is important to protect yourself. There are multiple VPN's to choose from, a popular one is NORDVPN.
5. Use a browser and search engine that values your privacy. Using a VPN won't help much if you are using software that does not respect your privacy (ie. GOOGLE products). I can recommend using Firefox or even Tor Browser if you want to be completely anonymous. Stop using google search and opt for alternatives like duckduckgo. For this step you have to do a little reasearch to find what suits you best.
I hope this helps.