waiver/contract

hi
i am going to do my first measurement . Do i need to get it in writing anything before starting the work? Do i need to have an insurance before i start working ?thanks for your suggestions

We have both E&O and Liablity insurance. Also, my staff is WorkSafe covered.

Errors and Omissions for measurements, General Liability for onsite property etc. Can add in equipment covereage as a bonus.

I am working alone . So I am thinking to go for E and O insurance only
. may be if I take both insurance gonna be expensive .