how long did it take for living standards to rise after mao got rid of the landlords and such?

It depends on which living standards. They eradicated mass opiate addiction, reduced houselessness, reduced food scarcity (by growing less opiates), increased access to health care, etc. All of these were possible with the backwards productive base of China at the time.

Although, widespread scarcity still existed. There was little access to electricity and other public utilities, few machines to assist agriculture, and few means of transportation (trains, cars, etc). These were all problems that could not be solved with China's productive base.

China's attempt to develop their productive base under Mao was a complete disaster. Due to horrible relationships with the CPSU, the Soviet Union did not assist them. And I don't think I need to delve into the failure of the Great Leap Forward.

China's solution to this problem was the Grand Bargain. They offered their massive labor force to the industrialized capitalist West. In exchange, China was given access to western industry, universities, and capital investment.

From this Grand Bargain, China has been able to rapidly increase the standard of living for people in the country, and break from the stagnation that plagued China in the 60's and 70's. Poverty has been eradicated. Workers and peasants have access to luxuries unimaginable 40 years ago: agricultural technology, electricity, public utilities, transportation, etc. More Chinese people support the Communist Party now than ever before

These are huge accomplishments, and a new development in socialist construction. However, there were trade-offs.

1. The Chinese bourgeoisie were given a more powerful role in society, because they became the liaison between China and the capitalist West.
2. The Chinese bourgeoisie do what the bourgeoisie always do: extract surplus value by any means necessary. This led to well-known cases of worker exploitation, such as the Foxconn and Apple incidences in the mid 00's.
3. China had to maintain friendly relationships with the capitalist West, or risk divestment. This ended China's effort to spread revolution to other countries. Instead, they advocate a platform of peaceful co-existence with all existing states.