The freelance rate conversation nobody prepares for

Setting a rate for a new client is a pricing decision. Raising one for an existing client is a relationship decision, which is why it gets postponed for years.

The mistake is treating it as a negotiation. It is an announcement with notice. You are telling someone what your rate will be from a date, not asking whether that is acceptable.

Give real notice, ideally a quarter. Do not explain at length, because a long justification invites a long discussion. Two sentences is enough, and the second one should be about continuing to work together.

Most clients say yes. The ones who do not were, almost always, the ones taking up the most time for the least money.