Everything changes with fashion. One moment your paisley shirt and baggy jeans seem tremendously cool, the next you realise you look like a fool. And so it goes with personal finance.
Barely a day goes by at the moment without some company launching a discretionary fund management service, or another person telling you that exchange traded funds or investment trusts are the only way to manage your money.
Open-ended funds, meanwhile, have gone the way of the paisley shirt.
There are undoubtedly flaws to unit trusts, not least the costs, but we have been banging on about that for years now.
On the positive side, competition has spurred on price reductions and any conversation about pros and cons in investing helps because it engages consumers in a debate about what is best.
But at the same time, we do also have a seemingly relentless tirade of positivity about investment trusts and ETFs – and the argument for both seems to hang around costs again.
Let us take the former for a moment, and it is useful as a starting point to look at performance.
There are plenty of managers out there who have both trusts and Oeics, so you can look at how they have performed almost on a like-for-like basis.
Nick Train, Alexander Darwall and Harry Nimmo all boast much better performance in their investment trust than in their mirror unit trust.
And so it goes for all but seven of 40 managers compared by fund platform AJ Bell. On the flip side, it found that volatility was much worse in the investment trust – no surprise there.
Plus, you have to focus on the net asset value in the investment trust, which has to be viewed separately to the underlying assets.
And then there is the gearing, and this is where analysis of investment trusts tends to get a little messy, because unless a retail investor goes in with their eyes open, it can be dangerous to assume investment trusts are working in exactly the same way as a unit trust, which are far simpler to understand.
The same can almost be said of ETFs.
They offer cheap ways to get exposure to the markets. But there is not enough debate about their liquidity and, indeed, their underlying assets, particularly when they are synthetic.
We are also in the wake of a 12-year bull run, where it has been very easy to make money and look like some kind of investment genius.
There is not much discussion about what happens to all those people exposed to equity markets in ETFs when this comes to an end.
What I am basically saying is that what we need is a little of everything.
But to simply reject one asset class in favour of another is damaging. Those pushing the pros and not the cons are doing more harm than good.
Has anyone counted how many different types of share classes there are now?