The work that trainees do varies a lot between firms depending on the type of case and client the firm attracts. It can involve a lot of nitty gritty research contributing to a much larger picture but trainees can also carry a large responsibility for dealing with a smaller client or case. For example, if you were doing a seat in property with a large commercial firm that was handling a corporate merger, you might be looking into an aspect of the detail of the estate of a major company. By contrast, in the property department of a private client firm you might find towards the end of your seat that you were doing most of the work on a domestic conveyancing case. In addition to the practical work, you have to do the Professional Skills Course which involves formal training and exams.
Trainees can spend a lot of time in mundane work.
While this can be a bit of a come down after the steep learning curve of the LPC the satisfaction of working on live legal cases and the development of professional practice skills can easily compensate. Applying for Training contracts Commercial firms of solicitors start to recruit trainees as early as two years before they expect them to start working. There is a guide to good practice that decrees that firms should not interview students before the September of the Summer before their final year of undergraduate study. In advance of this date, some firms offer, and interview for Summer vacation work. It is generally more difficult to get onto a vacation scheme with a commercial firm than it is to get a training contract.