Most collect levels punish you for spending the goal tile carelessly. A regrowing goal inverts that, and the levels built around it reward a completely different rhythm.
What regrowth changes
On an ordinary collect level the goal tile is a finite resource on the board, and the risk is exhausting it. On a regrowing level the tile replenishes, either from the refill in guaranteed proportions or through a mechanic that converts other tiles into it. The supply is therefore not the constraint. Moves are the only constraint, and that simplifies the level enormously once you notice.
The practical consequence is a reversal: on ordinary collect levels you take small careful matches of the goal colour; on regrowing levels you take the largest matches available, because there is no penalty for consuming the supply and every reason to convert moves into progress efficiently.
Telling the two apart
Nothing in the interface announces it, so the check is empirical and takes two moves. Clear several goal tiles and watch what arrives in the refill. If goal tiles come back at roughly the same density, the supply regrows. If the board visibly thins out in that colour, it does not.
Doing that check early is worth the two moves it costs, because the two level types reward opposite play and getting it backwards is expensive in both directions.
Two moves of reconnaissance at the start of a collect level is the cheapest information in the genre. It determines whether you should be spending the goal colour freely or hoarding it, and those are opposite plans.
Pacing against a regrowing target
With supply unconstrained, the level becomes pure arithmetic: goal remaining divided by moves remaining gives the rate you need. Check it at the start and again halfway, exactly as with any move-limited level.
The difference is what to do when you are behind. On a scarce level, being behind often means the level is lost, because the material is gone. On a regrowing level, being behind means you have been taking matches that were too small, and the fix is available immediately: hold for larger matches and specials, because the supply will still be there when you find them.
Boosters on these levels
Anything that converts a large number of tiles at once is unusually strong here. A colour-clearing special on a regrowing board removes every tile of the goal colour and the board simply refills with more, so the usual downside of stripping a colour does not apply.
This makes regrowing levels the best place to spend a saved booster, and the worst place to spend one on the failure screen afterwards. If you have a strong special available, these are the levels to use it on.
Combined goals
Levels that mix a regrowing goal with a finite one are the genuinely interesting case, and they are common in harvest-themed games. The rule is straightforward once stated: the finite goal sets the plan, the regrowing goal takes care of itself. Play the whole level around the scarce target, take the regrowing one opportunistically, and check the finite counter rather than the one that is moving nicely.
Getting this wrong is the standard way to lose these levels, because the regrowing counter races ahead early and creates a comfortable impression while the finite one sits untouched until the moves have gone.
Why designers use regrowth at all
It produces levels that feel generous while remaining precisely tuned, because the designer controls the move budget rather than the material. It also produces the satisfying stretch of play where a counter drops rapidly, which is a better experience than grinding out a scarce target and is one reason harvest-themed games in this genre have a reputation for being relaxing. The level is no easier; it is simply constrained in a way that feels less like a shortage.