There used to be a small cost benefit. 90-day plans worked out $2 cheaper than three 30-day plans. Until PM started to focus customers onto pre-built 30-day plans.
The data bucket could all be used up on the first or last of the 90 days, it was more versatile than three separate segments. So it was good for some niche uses, popular for those who didn't use much data unless going on vacation or whatever.
PM offered LTE data options on all plans back then, not just 90-day plans. Some customers still have these legacy plans.
I first signed onto PM with the "$90 90-day Fall promo" (which actually cost $88 through the old Build Your Own Plan calculator, $82 with AutoPay). It had Unlimited Province-wide Talk, Unlimited Canada-wide Text, 1GB data at LTE speed. I eventually changed it to the $25 plan, more Talk, more Text, more Data, lower cost ($75 for 90 days, $69 with AutoPay). The only thing I lost on this upgrade was the LTE data speed ... which wasn't really very useful with only about 4GB every year anyways.
So 90-day plans seemed great back then. But not so great anymore. I think most 90-day-era customers would have upgraded to newer 30-day plans which generally offer more for less. And I think anyone who's hung onto a legacy (low-cost promo) 90-day LTE plan for all these years will be reluctant to give or sell it away (along with their phone number and their accumulated Loyalty Rewards).
