A pulsator's outer housing and mounting typically outlasts its internal components by a wide margin — the diaphragms, valves, and seals inside are what actually flex and wear with every pulsation cycle, thousands of times a day, every day the machine runs. When pulsation timing starts drifting or a pulsator sounds or feels different than it used to, it's very often those internal parts wearing out rather than the pulsator itself failing.
The Pulsator Kit is built for exactly that situation — rather than replacing the whole pulsator unit, you rebuild it with fresh internal components, which restores accurate timing at a fraction of the cost of buying a new pulsator entirely. It's worth trying this route first whenever a pulsator's performance has degraded but nothing about the unit is physically broken or cracked; a full pulsator replacement is the right call only once the housing itself is damaged or the unit is old enough that a rebuild doesn't make economic sense anymore.