The work experience that you do to get in to medical school is really important - this is something that every admissions officer is looking for to prove that you are interested in and committed to the idea of becoming a medic. Its also important for you that you get a real flavour of what working in healthcare is really like, as some people find that this is actually not an environment that will suit them when they qualify.
You will be asked directly in most interviews to discuss your work experience, but you must be careful not to fall into the trap of talking about what you learned from a medical point of view only, as while this is interesting it is not the main goal of completing these placements. Interviewers want to hear about the skills that you witnessed in those around you, and any that you may have developed yourself as a result.
For example, understanding the importance of good communication between doctors and their patients is something that you are likely to have observed no matter where you've been. Interviewers want to hear about moments you may have witnessed where a doctor developed a good rapport with a patient which allowed them to open up about something they may not previously have wanted to. Being able to recognise this is vital for your future practice, as patient's are unlikely to be open and honest with you unless you are the same with them.
Another important thing to consider when you are arranging your placements is whether you are managing to see a variety of clinical situations. Hospital medicine is a very wide area with mamy specialties, however at your stage the general rhythm and activities are likely to be similar regardless of specialty. Experience in nursing or residential homes is one way to gain insight into a completely different environment, and allows you to see how other members of the multidisciplinary team contribute to care. This is particularly important, as doctors do not act alone, and being able to recognise the importance of the input of various members of the team and problem solving together is another key message. You may also benefit from shadowing other healthcare professionals, such as physiotherapists, occupational therapists, nurses and radiographers to broaden your experience, and see how each aspect of a patient's care feeds into the bigger picture. If you are considering a future in research, you might want to get in touch with an academic consultant who can give you a flavour of what it is like to split your time between research and clinical medicine.
Ultimately, whatever experience you manage to gain can only be helpful; it is learning to pull the important themes and skills from these placements and discussing their importance that is likely to gain an interviewer's interest.