A word of advice. Never, ever set yourself up for this if you're a solo freelancer, unless there's 3 of you (or at a pinch 2).
The time the client needs this will be when you're a) on an airplane b) in bed with the flu c) on holiday d) having a romantic evening/weekend with your other half.
Nice money and the client likes it, but you have signed away your entire life in exchange.
Maintenance is a monthly fee, forgot to mention that. Sometimes clients do call in unfortunate situations, but they pay for that privilege. All additional services are opt-in.
A word of advice. Never, ever set yourself up for this if you're a solo freelancer, unless there's 3 of you (or at a pinch 2).
The time the client needs this will be when you're a) on an airplane b) in bed with the flu c) on holiday d) having a romantic evening/weekend with your other half.
Nice money and the client likes it, but you have signed away your entire life in exchange.