What is the meaning of the phrase 'As a rule'?

• As a rule
English Meaning: usually, but not always.
Bangla Meaning: সাধারণত কিন্তু সবসময় না।

Ex. Sentence: I go to bed at 10 p.m. as a rule.
Bangla Meaning: আমি সাধারণত রাত দশটায় ঘুমাতে যাই।

• অন্য অপশন গুলোর মধ্যে - 
 • As good as
English Meaning: very nearly / almost / nearly.
Bangla Meaning: প্রায়।

• As much as
English Meaning: almost but not quite / even though / almost.
Bangla Meaning: প্রায় সমান / প্রায়।

Source: Website Lecture.