Liaoning is in the water since 19 Mar 2010. Time for the ship to enter the drydock then?
I would take her from the date of commissioning and go from there.
expect she will hacve a 30-40 yer life time, so her big mid-life dry dock stay (the longest) will probably occur in 2028-2032 time frame.
She will probably have another one half to the for dry dock maintenance, and another at the 3/4 period.
Other maintenance will occur...but a scheduled dry dock time foe her may occur in 2020 time frame or so.
If there are issues, problems, or breakdowns requiring it, she could go in before that at any time...but that's what I would project...again realizing that I do not know how the PLAN has set up their scheduling and life time for the carrier.