A subscription is worth it once your charging adds up to more than the fee itself, and no sooner. That threshold is called the break-even point, and you can compute it in less than a minute with your own numbers.
What a subscription actually buys you
A charging subscription usually works the same way everywhere: you pay a fixed amount each month, and in exchange the network drops its per-kWh (or per-minute) rate for you. The pay-as-you-go rate stays open to everyone, subscriber or not, but it's higher.
That structure means a subscription is really two numbers stacked together: a fixed monthly cost, and a discount that only pays for itself once you've charged enough to eat through it.
The break-even formula
The math is simple division: break-even kWh = monthly fee ÷ discount per kWh.
Say a subscription costs €7.90 a month and knocks €0.10 off every kWh you charge on that network. You'd need to charge 79 kWh in the month just to cancel out the fee. That's roughly two full charges on a mid-size EV battery. Charge less than that, and you paid for a discount you didn't use up.
Push the discount higher, say €0.15 per kWh for the same €7.90 fee, and the break-even drops to about 53 kWh, less than two charges. The bigger the per-kWh discount, the sooner a subscription starts saving you money rather than costing it.
The catch: it's per network
A subscription discount only applies on the network that sold it to you. If half your charging happens on a different network entirely, that half never touches your subscription rate. Your real break-even point isn't your total monthly charging, it's the share of it that happens on that one network.
Check your last three months of charging sessions. If most of them cluster on a single network, a subscription is worth pricing out. If they're scattered across five or six, the pay-as-you-go rate is probably still winning, because no single subscription is discounting most of your sessions.
Watch the commitment, not just the fee
Some subscriptions lock you in for a minimum term, or auto-renew unless you cancel a set number of days ahead. A discount that looks good on paper is worth less if you're paying the fee for months you don't drive much, over the winter for instance, or during a trip abroad where the network barely operates.
Redo the break-even math with your real, driven numbers, not an average month, and you'll know within a minute whether the card in your wallet is earning its keep.
Flexibility has a price too
Staying pay-as-you-go everywhere means you never carry a fixed cost, but it also means you never unlock a discount. For drivers who charge on a rotating mix of networks, that flexibility usually beats any single subscription, simply because no one discount covers most of their sessions. Comparing case by case, station by station, remains the safer default until your own numbers say otherwise.