Should we always hold our Boules when playing rather then a lot of droping and picking up?

There's no rule against holding unplayed boules or not, and I leave it up to each player to decide as sometimes, holding all three boules can be a distraction for a player - especial one who doesn't have lots of hand strength.

There is a kid of boule-clip holster I've seen where boules are "clipped" into a bent-metal chassis - sort of like a petanque Batman utility belt. For this I'd advise the player make sure their belt is secured tightly else they may find their pants falling to their ankles!

I used to know one chap that used to keep boule in his pockets and once pulled out an apple!

I personally find it more natural to carry all three ball in my hands. It also makes it look like you know what you are doing and perhaps more importantly, you don't forget to play any of your boule.

Not always .You cannot hold a spare boule while playing your last.
ie in triples carrying three and playing two.