Long Life Spikes

"Spikes last much longer and can carry over one round."

- In-game description

 is the 3rd upgrade of Path 3 for the Spike Factory in Bloons TD 6. The spikes from this upgrade can last in between rounds (2 rounds or 140 seconds, whichever comes first). This allows spikes to carry over another round from the round they were created. Spike piles from this Spike Factory resemble Caltrops thrown from a Ninja Monkey, except the spike piles from Long Life Spikes are blue instead of grey (or hot yellow with 2-0-3).

It costs $1,190 on Easy, $1,400 on Medium, $1,510 on Hard, and $1,680 on Impoppable.

Tower Prices

 * Updated as of Version 29.4

Summary
Long Life Spikes is a rather expensive but versatile upgrade once purchased. By allowing each spike pile to last between rounds, it is possible to stall rounds in order to stockpile many spike piles that can become carried over to the following round. Generally speaking, when attempting to pursue towards maximizing the potential of Long Life Spikes, it is worth purchasing Faster Production and Even Faster Production alongside to allow maximized net popping power stockpiles. Similar to the much more powerful Perma-Spike, Long Life Spikes is a deadly force when combined with Berserker Brew/Stronger Stimulant and Jungle Drums. Similar strategies can be used for the succeeding upgrade Deadly Spikes.

Long Life Spikes (and its successor) require external support to be closer to the viability of Spiked Balls later in the game. Berserker Brew and Stronger Stimulant are good examples of external supports, which providing it with +1 damage and +2 / +3 pierce.

This upgrade enhances Spike Factory's stockpiling potential and it is recommended to be used for defensive purposes to maximize its efficiency.

Tips

 * On single-entry-single-exit maps, always place a Long Life Spikes near the end of the bloon track. Then spikes will not be used up immediately, allowing spike stockpiling to slowly make the tower more and more valuable.
 * It is recommended to purchase the Path 2 Upgrades (Faster Production and Even Faster Production) over the Path 1 Upgrades (Bigger Stacks and White Hot Spikes) as Bigger Stacks only increases its pop count per spike from 5 to 10 and although White Hot Spikes allows it to pop any DDTs that may rush through the player's defense, a Monkey Intelligence Bureau or Acidic Mixture Dips can easily solve that problem while also providing it and other nearby towers with the bonus as well.
 * Path 2 upgrades will add +79% extra pops with a fast refresh, while Path 1 upgrades will add +100% extra pops with a slow refresh and allows Lead-popping. While 2-0-3 is better at overall spike production, 0-2-3 is much faster and synergizes much better when paired with Alch buffs.
 * Avoid leaving the game, as the stockpiled spikes do not carry over between saves.
 * Long Life Spikes does NOT decrease spike amount when purchasing Bigger Stacks.
 * In Apopalypse Mode Long Life Spikes outside of increased lifespan are less useful as spikes without this upgrade do not disappear at the beginning of the next round.

Trivia

 * The spikes produced by Spike Factories with this upgrade look somewhat similar to the Caltrops that Ninja Monkeys use.
 * This spike factory appearance mostly resembles the Bloons TD 5's MOAB-SHREDR Spikes upgrade.
 * Prior to the rework of Overclock's ability, double-discounting the whole 0-2-3 Spike Factory with two Monkey Commerces was used to make an Overclock on Perma-Spike last 15 seconds longer. This is because this discounting would bring down the total cost of the 0-2-3 Spike Factory to ~$3,752, thus bringing down the total cost of Perma-Spike to be ~$39,932, barely below the threshold for Overclock's duration penalty for $40,000+ towers.
 * Now, Perma-Spike overclocks will only last 30 seconds.