I am at a loss to understand the very question. Switching jobs is the personal choice of the individual employee concerned. The reasons may vary according to the individual's needs and perceptions. Even after a small stint of 2 months in a company, if the sole reason prompting voluntary exit is salary, naturally the person would expect some hike according to his expectations from a new employer. It is for the prospective employer to assess the potential of the employee to find out any mismatch between the demanded hike and the capability of the employee. Every job has its own minimum skill-sets and a corresponding compensation package according to the industry. One can not presume that under-qualification of an employee or previous short tenure alone essentially results in the same salary in a new job. There can be other reasons too.