There isn't really a one size fits all answer to this as it very much depends on your tolerance for risk, investing horizon and goals.
For someone young, I would always suggest going higher on stocks and shares. This way, you can expect to receive higher average returns over time (with fluctuations along the way) and unlike cash the money is protected against inflation.
If however, you're close to retirement, investing in to stocks and shares for a major part of your portfolio may not be a good idea. Example: lets say you retire in 3 years and... (More)