Intertemporal optimization

An agent lives for two periods: in the first period she works and in the second period she is retired. The income in coins (salary) for this agent is w₁ > 0 and the income in coins (national pension) in second period is w₂. The agent has the utility function. u = log(c₁) + log(c₂). Where c₁ is consumption in the first period and c₂ is consumption in the second period. We assume that > 0.

How do you interpret and what would be reasonable to assume about (besides > 0).?