Do your users create duplicate records? Is it not comfortable for you to see that you probably created a duplicate after you filled the whole client card?
None Duplicates add-on alerts you for possible duplicate right after you fill a basic information such as a company name, company ID or address. Among others, this add-on tells you, which of your colleagues already owns the existing customer, which you want to create again. None duplicates also allows you to create combinations of conditions. You can use it for example when you have two accounts with the same name and ID, but on different addresses. You can also check leads according to accounts and conversely. Thanks to this settings, module prevents to create a lead, which already exists as account.