Anglų kalbos kursas: Habits

NOTE THE DIFFERENCE 

Use present simple for permanent or repetitive actions in the present, e.g.
                  I work in finance.

Use present continuous for temporary actions in the present, e.g.
                  I am working on the report this week. 

Use present perfect for actions, when you want to say how long they have been ongoing, e.g.
                  I have worked for my current company for two years.
                  I have worked on this report for two hours. 

PAST SIMPLE vs PRESENT PERFECT

Use past simple for past actions when the exact time is given and the period is finished, e.g.
                        Tomas sent the report last Friday - five minutes before midnight. (exact time - last Friday - the period is finished)

Use present perfect for past actions when exact time is not given or the period is not finished, e.g.
                         Tomas has missed three deadlines this month, and it's only the 6th. (the period is not finished)
                         He has promised to change... many times. (the period is not given)