Instance: m5.large (2 vCPU, 8 GB Memory), running Amazon Linux
Region: US East (northern Virginia)
On-demand (pay-as-you-go): $0.096/hour
Standard 1-year Reserved Instance, all paid upfront: $501 ($41.75/month)
If this instance is expected to run for more than 435 hours each month, consider a 1-year reservation.
If this instance is expected to run for less than 435 hours each month, use an on-demand payment model.
Scenario A: This m5.large instance is being used for user-acceptance testing of application updates. New updates are released on average once every 4 weeks, and testing takes about 5 days for each release. We can assume that this instance is needed for 120 hours/month (1 release/month, 5 days/release x 24 hours/day = 120 hours/month)
Outcome: Since the expected usage is less than the break-even point (120 < 435), using an on-demand payment model is recommended.
Scenario B: This m5.large instance is being used as a development environment for an application whose developers are located in India (GMT+5.5), Ireland (GMT+1) and California(GMT-7). Due to the differences in working hours for the development teams, this instance is in constant use, except for a period of 36 hours each weekend. We can assume that this instance is needed for 586 hours/month (730 hours/month – 36 hours/weekend x 4 weekends/month).
Outcome: Since the expected usage is more than the break-even point (586 > 435), purchasing a 1-year reservation for this instance is recommended.