Adult training is a fundamental strategy for the improvement of workers' skills and employability. However, as workers age and remain in the same company, the risk of losing motivation for learning may grow. In a sample of 1,452 workers from 17 Spanish companies, we analyzed to what extent the training factor increases their quality of employment and the assessment they make of their organization, despite the negative effect of the passing of time. To do so, we implemented a structural equation model that considered the effects of the variables "seniority in the company" and "training" on quality of employment. We tested this model through multigroup analysis by differentiating between workers aged under 50 and those aged 50 years and older, showing that the positive effect of training is stronger in older workers and reduces the negative effect of seniority in the company for those aged under 50.