iStat Menus has been the standard answer to "what is my Mac actually doing" since the PowerPC era, and version 7 is a rewrite rather than a fresh coat of paint. You choose which readouts sit in the menu bar — processor load, GPU, memory pressure, disk activity, network throughput, temperatures, fans, battery — and each one opens a panel with history graphs and the processes responsible for the spike you just noticed.
$11.99 buys a single licence from Bjango or Apple. $14.99 covers up to five people in a household, which is the better deal for almost anyone with more than one Mac in the house. Owners of version 6 paid $9.99 to move to 7, and that is the shape of the arrangement: you own what you bought, and a new major version every few years asks for money again.
The weather module is the part that annoys people. A licence includes six months of it, after which the forecast wants $0.99 a month. Every sensor, graph and menu bar readout is unaffected.
If all you want is CPU and memory numbers in the menu bar, Stats does that for free and does it properly. What the money buys here is the presentation, the depth of configuration and the family licence.






