Similarly, for my windows account, I have a strong base password (upper, lower, numbers and special characters) and I add a counter after. I just write the current counter under my keyboard. For other company software or machine requiring another credential, I use the name of the system then the same base password and another counter (the counter is also written under my keyboard)...
eg: base password: My5trongB4seP@ssw0rd
Under my keyboard, I have:
Yes If they crack one of my password and devise the methodology they can enter in all my systems at work. But I have run my base password against 3TB of rainbow tables (MD5, LM, SH1, NTLM) and the 2014 password list I could put my hand on (25M pwd) with success to have some confidence in it it will not be cracked so easily.