Does the time difference between Lagos and Toronto change during the year?

Yes. Because of daylight saving time the gap moves between +5h and +6h.

When is the best time to call Toronto from Lagos?

Between 14:00 and 17:00 in Lagos, which is 09:00 to 12:00 in Toronto.

Lagos is 5h ahead of Toronto. This gap is not fixed: daylight saving time moves it between +5h and +6h during the year.

Lagos

Nigeria

--:--:--

Toronto

Canada

--:--:--

A 9-to-5 day in each city overlaps for 3h. That is 14:00–17:00 in Lagos, which is 09:00–12:00 in Toronto.

City	Time zone	UTC offset
Lagos · Nigeria	Africa/Lagos	UTC+1
Toronto · Canada	America/Toronto	UTC−4

What is the time difference between Lagos and Toronto?: Lagos is 5h ahead of Toronto. This gap is not fixed: daylight saving time moves it between +5h and +6h during the year.
Does the time difference between Lagos and Toronto change during the year?: Yes. Because of daylight saving time the gap moves between +5h and +6h.
When is the best time to call Toronto from Lagos?: Between 14:00 and 17:00 in Lagos, which is 09:00 to 12:00 in Toronto.