Present perfect with an incomplete period

The present perfect tense is used to express actions happening in an incomplete period of time. An incomplete period is one that includes the present moment, that is, the time of speaking. This period can be implied or expressed with a time expression (today, this week, this year, ever, never etc.):

I haven't smoked today.
I've lived here all my life.
Have you ever been to China? (in your life)
My uncle has written several plays. (in his life, supposing he is still alive)
He has never worked as a waiter. (in his life)

If the action happened in a completed period of time (one that does not include the time of speaking), the past simple tense is used. This period can be implied or expressed with a time expression (yesterday, last week, last year, between 1905 and 1910 etc.) or a clause:

I didn't smoke yesterday.
I lived in this house when I was a child. (I am not a child any more)
Did you go to China when you were working as a flight attendant?
Shakespeare wrote numerous plays. (in his life, he is dead now)
He worked in this café between 1905 and 1910.

Note that some time expressions (e.g. this morning, recently and lately) may refer to either a completed or an incomplete period of time depending on the context and whether or not the time of speaking is included in the given period:

I have seen him this morning. (it is still morning)
I saw him this morning. (it is later during the day)

He has put on some weight recently. (in the past few days/weeks/months etc.)
He put on some weight recently. (some time ago)

Reference to an incomplete period of time, however, does not always involve the use of the present perfect tense:

Have you been to Lake Balaton this year? (any time this year)
Did you go to Lake Balaton this year? (at the time when you go there every year)

Although both actions are related to an incomplete period, the present perfect in the first sentence refers to an indefinite time; meanwhile, the past simple in the second sentence implies a definite time (supposing the recipient of the question always visits Lake Balaton at the same time every year).