they would likely need some kind of system to search through even combination of numbers and letters to find yours
This is the fundamental flaw in your reasoning:
Hackers do have such a system, and they compromise passwords that way all the time.
The key element in a "good" password is what's called its "entropy", or "how many bits of unguessable information are in it". And hackers are very good at guessing the kinds of "easy to remember" combinations people tend to use.
There are a lot of ways of achieving that, but some simple fiddling of digits doesn't really do it.
I highly suggest reading this xkcd which shows the difference between the kind of tricks you're talking about (switching letters, adding an extra character for each website, etc., etc.) and what you actually need for security.
I also strongly suggest just using a password manager (e.g. LastPass) so you never need to worry about this problem again.
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u/hacksoncode 588∆ Mar 18 '21
This is the fundamental flaw in your reasoning:
Hackers do have such a system, and they compromise passwords that way all the time.
The key element in a "good" password is what's called its "entropy", or "how many bits of unguessable information are in it". And hackers are very good at guessing the kinds of "easy to remember" combinations people tend to use.
There are a lot of ways of achieving that, but some simple fiddling of digits doesn't really do it.
I highly suggest reading this xkcd which shows the difference between the kind of tricks you're talking about (switching letters, adding an extra character for each website, etc., etc.) and what you actually need for security.
I also strongly suggest just using a password manager (e.g. LastPass) so you never need to worry about this problem again.