I saw this phrase yesterday in an email message.

Problem:
The noun “observance” is the wrong one for this phrase.

Explanation:
The phrase appeared in an email message about what an observer saw.

The phrase introduced the list of what he observed in subsequent days when he watched troubleshooting agents use a particular software application.

The noun “observance” has some eight definitions, the most popular of which include

• an act of conforming to,
• a celebration by appropriate ceremonies, and
• a ceremony for a particular occasion.

Given that observation is one of the least popular definitions of the noun “observance”, it is best to avoid using “observance” when “observation” is the much clearer noun.

Solution:
“Next days of observation of agents’ use of the tool”