Way back when I started playing World of Tanks there were only three skills a crew could train after learning their main qualification (commander, driver etc.) and these were Camouflage, Repair, and Firefighting. Then in (I think) 7.2 – it was fairly soon after I had started playing – the number of skills was massively expanded. One of these was the Mentor skill, which is associated with the Commander. Essentially it allows other crew members to acquire experience at a faster rate – 10% faster when fully trained.
Initially I had a number of commanders start the Mentor skill. My decision in doing so was informed by my experience of learning skills with EVE where there was a simple trade-off – time of skill learned versus gain. In EVE learning skills creating a lot of heartache, and eventually CCP did away with them. For the record I trained them all to 5, knowing that particularly with the Charisma skills I was unlikely ever to recoup the time taken up in training.
In EVE the time taken up in training (when one could have been training something else) was basically the only ‘negative’ of the learning skills. In World of Tanks though I have come to the conclusion there is a much higher cost. It is a relatively simple thing, and in a sense I am embarrassed I did not consider it sooner.
In World of Tanks the amount of experience for each skill takes twice as much as the previous skill. In practical terms for me, this means that most of my crews that are learning skills are still working on the first skill after the major qualification. I have three tanks currently working on the second skill, and one on the third. That means that for the majority of my tanks the Mentor skill – which gives no ingame impact – is taking up a slot that could have a significant performance increase in my gameplay. This is particularly true because there are some very tempting skills a Commander can train instead of the Mentor skill.
So I have bitten the bullet, and retrained all my commanders that had the skill and replaced it with something else. For my Marder II commander I used gold (half-price at the moment, and my last 100 gold) as recently my Marder II crew has already and a skill re-train and lost some progress as a result, and I didn’t want him to be hit a second time. For everyone else however it was a credit retrain. Mostly I have replaced it with the Recon skill – but not exclusively. My Hummel commander is now learning Sixth Sense, and my KV-1 commander now has Eagle Eye (which is something of a test in and of itself to see how that works – I may retrain him to something else yet).