Since its inauguration in 2005, the Atacama Pathfinder EXperiment (APEX) Observatory has steadily evolved into a mature project, while still preserving its experimental character. On one side, a continuous technical refurbishment keeps instrumentation competing on the front line: more than a dozen different instruments, between spectrographs (heterodyne instruments) and imagers (bolometer cameras) have been commissioned in these years and several more are under development and will be installed in the next years. On the other side, observing efficiency has been continuously improving, therefore allowing to maximize the scientific output of the telescope. Key aspects to achieve this efficiency are: (i) a scheme of 100% service mode observations which permits making the best use of the outstanding weather conditions over the Chajnantor plateau; (ii) the implementation of a 24-hours observation strategy, a challenge for a low-staffed observatory, which allows APEX nowadays to be on-sky close to 4000 hours per year and forces to a more intelligent scheduling of maintenance and technical tasks; and (iii) the standarization of observing, data reduction, quality assesment and archiving procedures, which minimizes telescope idle times and streamlines the data flow from the telescope to the PIs. All these improvements have naturally resulted into a substantial increase of data volumes produced over the years: our next generation bolometer cameras will have thousands of pixels, compared to a few hundred in current instruments. Heterodyne receivers have more than doubled their bandwidth, and the spectral resolution has been improved by increasing the number of channels by a factor of eight. In the last two years we have developed and implemented a new automated data transfer system, from APEX to the ESO archive in Garching. This significantly reduces the lag between data being taken and the PI getting them. This new transfer system allows to deliver the data within 2 days, closing the loop with the PIs. They can now provide feedback while observations are still ongoing to improve observing strategies. An additional challenge has been to align the APEX archiving procedures to get a sub-mm observatory integrated into the ESO data flow system, which has been designed for optical observatories like Paranal or La Silla.