Primary Mentoring

"All Primary Monkeys in radius get tier 1 upgrades for free, increased range and reduced ability cooldowns."

- BTD6 description

Primary Mentoring is the fourth upgrade of Path 1 for the Monkey Village in Bloons TD 6. It allows all Primary Monkeys within its radius to be granted free Tier 1 upgrades, alongside the benefits of Primary Training. Starting from Version 17.0, it also grants nearby Primary Monkeys with +5 range and reduces their ability cooldowns by 10%.

It costs $2,125 on Easy, $2,500 on Medium, $2,700 on Hard, and $3,000 on Impoppable.

Summary
Primary Mentoring further improves exclusive buffs for nearby Primary Monkeys by extending the Primary Training effect to also include free Tier 1 upgrades, reduced ability cooldowns, and even more range. In addition to strategical advantages provided by Primary Training, the allowance of free Tier 1 upgrades makes it less costly to spam in more Primary Monkeys within range, in addition to allowing Primary Monkey abilities to be activated more often. Since the Primary Mentoring range buff is additive, rather than multiplicative, its extra range benefit is greatest on low-range towers, namely lower-level Ice Monkeys and Tack Shooters.

The value of the Primary Mentoring upgrade benefits makes this upgrade see its highest use in combination with Striker Jones + MOAB Mauler spam strategies. The free Tier 1 upgrades portion of the upgrade allows more MOAB Maulers to be added within range, saving a significant amount of money in the long-run to compensate the expensive supports provided by the Village. On the other hand, the MOAB Maulers benefit well from the extra range and all other preceding Village supports, while the reduced ability cooldowns increase the viability of MOAB Assassin abilities versus spaced blimps. Other popular supporting Primary Monkeys also can benefit much from this upgrade's various supports, specifically MOAB Glue, MOAB Press, Bloon Impact, and 0-1-2 Re-Freeze Ice Monkeys.

Tips

 * For the free Tier-1 upgrades, Primary Mentoring is best used with Bomb Shooters, as their Tier-1 upgrades collectively are the most expensive of their kind.
 * The two most expensive Tier-1 Bomb Shooter upgrades are Bigger Bombs ($350 on Medium) and Faster Reload ($250 on Medium), saving up to $600 on Medium.
 * As such, certain Striker Jones + Bomb Shooter strategies, particularly with either masses of MOAB Maulers or Recursive Clusters, will benefit the most from the discount portion of the Primary Mentoring upgrade. For 2-0-4 Recursive Clusters, this discount is slightly less than that for 1-3-0 MOAB Mauler spam, but each 2-0-4 Recursive Cluster can save to $550 on Medium ($350 + $200, Medium prices) per Bomb Shooter if upgraded within range of the Primary Mentoring.
 * Primary Mentoring works well with Primary Monkeys that have abilities, such as Super Monkey Fan Club, Super Maelstrom, Turbo Charge, Glue Storm, and MOAB Assassin.
 * Primary Mentoring's +5 range bonus is additive on top of the multiplicative +10% range bonus from Primary Training. As such, this particular bonus benefits the most for Ice Monkeys and Tack Shooters.
 * Because of the tiny ranges of most Ice Monkeys and Tack Shooters, the +5 range buff is much more significant of a range increase for those tower types.
 * This especially empowers the Super Brittle + Tack Zone synergy, because these two towers hand-in-hand support each others' weaknesses; Super Brittle is a poor damaging tower on its own, but its massive damage debuffs against affected bloons plus its moderately adequate stalling power against Super Ceramics allow the Tack Zone to reap up large amounts of damage, especially against Super Ceramics, the bloon types that Tack Zone may typically struggle heavily against.
 * Generally speaking, the effective crosspathing for the Primary Mentoring depends on the situation. In most cases, however, a 4-2-0 Primary Mentoring is more desired to grant camo detection to nearby Primary Monkeys, although 4-0-2 Primary Mentoring is not a bad option for further saving a good chunk of money for more expensive lower-tier Primary Monkeys.

Trivia

 * The most expensive upgrade that can be purchased for free with Primary Mentoring is the Bigger Bombs upgrade from the Bomb Shooter, saving $350 on Medium each.
 * The most expensive combination of upgrades that become free by the Primary Mentoring benefit is the Bomb Shooter with Bigger Bombs and Faster Reload, totaling a saving of $600 on Medium each.
 * Even though Primary Mentoring was buffed in Version 17.0, the description was not changed to accommodate the bonus benefits until Version 18.0.
 * Version 18.0 fixed that issue; the new Primary Mentoring description now expands upon the original version of it.
 * In Version 17.0, there was a bug where upgrading to Primary Expertise did not grant the special Primary Mentoring bonuses to nearby Primary Monkeys. This was fixed as of Version 17.1.