Just don't...

It's a net loss using crons on 90% of the items.

I don't recommend any new players to follow this advice, you really don't need to cron anything until end-game truthfully. It always depends on the person of course, but I would not cron most things like @CatDK had mentioned.

If any new players are reading this, just ask in-game or on the Official BDO Discord about when you should use crons and if your failstacks are in a good range for enhancing. Most people will guide you in the right enhancing direction if you just ask!

I can see where the OP is cooming from.

And he is propably right.

A new player has other problems then "doing math" to see if something worth... A new player needs to be Motivated and Hooked into the game first...

7 out of 10 New people, will uninstall the game instantly if they realise an item can downgrade, so using cron stones atleast doesnt make the people quit the game.. (Yes some German Streamer showcased BDO and doing a little project about BDO, and arround 70% of players from twitch chat said they uninstalled the game the moment an item downgraded)

We also had a very nice discussion with the German Streamer Entenburg yesterday. He is super casual and showcasing the game. And the conclusion we had was. "Pearlabyss need to solve the problem with the enhancint at the ROOT, and not shoveling sugar-candy on top of everything.. All the free stuff and popups we have right now will make new people instantly not want to play the game at all..."

The Veteran might not realise it. they need to step out of the bubble and thing like this:

There a million games out there, a new player just bough BDO in a Sale or got for free.. Graphic is nice, they try out the game....

Then they get their First Naru Gear... They click that thing, realise That thing can fail? wtf.  and already are a bit turned down, and want to play something else..

Then they realise at DUO if they fail they LOSE progress.. and then most people are done already.. they instantly close the game. and go back to their other games.

Negative Item progression is one of the most hated thing in the whole MMORPG franchise, shortly after P2W and Forced Open World PVP.

Guess why they makeing season easier and easier every time.. cause they need Hook new people.. but they will never hook new people in the long run, cause of NEGATIVE ITEM PROGRESSION.

I am not going to spend a cron stone for a tuvala. Let alone a naru. KeKz. Materials for these are in abundance. And failstacking is something to be considered doing too.

Asking in-game gets a new player nowhere,as he/she will be scolded (go search on google! is a thing some will yell or they refer to some youtube channel)  or that people tend to give false information. There are some exceptions and often on the season servers there is help, but if there is one thing that is for sure that is that this community is just toxic. I try to help people myself as much as i can. 

As for cron; green items; don't. Naru; don't. Tuvala, only the last part then and you can upgrade tuvala already to TRI with one enhancement (it will cost you durability). But normally people save it up for boss gear, as that is the hardest to enhance. 

Made some adjustments / corrections for you.

My simple suggestion:

Just remove degrading and , in case of rings, belts and so on, destruction. Durability loss is ok, maybe raise it a bit to make it a little harder and a bit more expensive. Done. The only reason they keep spamming free things that are easier to upgrade is to keep new and/or casuals ingame. And yes, i keep using crons on Tuvula for pen, or less for Accessoirs because i have no interest in a piss me off enhancement system, this is why i dont have pen high gear to date. BTW, i spend only free crons they spam into the game to keep the non masochist players.

Now have fun in disliking

Those are not corrections. 

Nothing wrong with using a few crons to get tuvala to PEN, otherwise you never get it. Unlike naru tuvala fails far more. With naru it's just slam, slam and presto. Tuvalu, starting then from TRI, if you're lucky you get to TET then and then it goes all the way down if you try the same way as naru. Even if using a sufficient failstack it will fail, cause of the wonderous thing called RNG.