If you type the same details over and over for the same clients, an easier and faster way of doing this is by using the duplicating option in the Time and Expense screens.
After you save an entry you can always open the entry from the Dashboard, Time/Expenses, in the Project, on the Invoices, as well as from a Report. After opening an entry you will either have a "Save & Duplicate" button or just a "Duplicate" button. If you see the "Save & Duplicate" button that means the entry has not been invoiced yet. If you only see the "Duplicate" button that means the entry has been invoiced.
Opening an entry and clicking "Save & Duplicate" or "Duplicate" will refresh your screen and leave with the duplicate entry on your screen completely filled in. From here you can change whatever you need like the client, project, description, activity, hours, etc. When finished you can Save & Duplicate again if you are working with the same clients or details or Save & Close to close the entry.