Here a case study of my past 15 month (since then i have my current phone subscription):
comments: i got this salt abo at christmas 2017, it is the smart swiss abo, including unlimited data, calls & sms in switzerland for CHF 19.95/ month (christmas deal 2017).
since i got a job on october with a phone plan that would cover all this (private) usage, i am eagerly waiting for cancelling this abo…
sms: i hardly use. basically only when i am forced to by people that dont support alternatives as whatsapp , skype or threema
calls: i am a low user with ~30 mins per month on average, and even less if i consider the recent rise which comes from my phone using my private number by default, so lots of company calls are in there. some few calls with my parents outside of switzerland
data: same here, 1gb on average including the recent rise, when i started using my phone as hotspor for job-related stuff
cost: i hardly ever pay the base price. on average 30 per month, that is 50% more that the base price. i feel squeezed out like a lemon. i even once (successfully) requested to remove chf 30 from my bill after some 5kb of data outside of europe leaked through my account, despite counter-roaming measures.
conclusion: i need a new private provider, probably some pre-paid, since all consumption is covered by my employer. in case this changes, i now have a solid bases to decide on my future plan.