It depends on what you HODL and when... this makes all the difference...
If you buy now a good coin/project, than I can sign under HODL is advisable!
But HODL/Investment in shitcoin is probably never advisable...

On the other hand HODL at the wrong moment, it doesnt matter whether it is good coin or shitcoin, is not advisable. For example in Dec 2017... But you need to understand, that whoever is hodling for a really long periods, for example from 2012, is doing great, despite all ups and downs...