Ascientist would most likely need to update her model when it has become too simple. no longer supports the latest results. reduces the need for verbal explanation of data. no longer appears interesting.

Answer is: no longer supports the latest results.
In chemistry for example: model of atom have been updating during 20th and 21st century because of new discoveries and new experimental results. Beginning with Thomson model, than Bohr model and lastly quantum mechanical model.

During photosynthesis, plants transform electromagnet energy from the sun into chemical energy.