This is where liquidity providers come in. Unless you are trying to be a routing node, the only outgoing liquidity you need is what you plan to spend. You can buy incoming liquidity for whatever you need to be able to receive.
Discussion
Most people will not need to be a full fledged routing node.
The incoming liquidity is usually only good for a set amount of time then you have to repurchase? Also one channel isn’t sufficient you’d need multiple correct? I don’t need to be a routing node.
It would depend on the provider and their terms as to how long the channel stays open. Multiple channels with different nodes will give you more redundancy if one channel goes down, for instance.