Depends what you are wanting to do, e.g. are you focussing on dividends or interested in a specific sector? I’ve been investing 6 months and I’m currently at 23 different investments, the impression I have is that around 30 is the average number but varies.
There was a really useful thread where we all posted our portfolios, will give you an idea of how many individual investments people have and what they are investing in but obviously do your own research. The thread is here: What’s your allocation?