A letter or an email arrives from a supplier: prices are going up by a stated percentage from a stated date. It reads as a notification rather than a proposal, and the usual response in a small business is to absorb it, note that things are getting more expensive, and carry on. That reaction is understandable - the supplier is larger, the alternatives are unknown, changing suppliers is disruptive, and the increase on any single item looks small. It is also, quite often, a more passive response than the situation calls for.
Price rises are more negotiable than they appear, particularly the ones announced across the board to every customer at once. A general increase is a blanket measure; it is not usually a considered judgement about your account. A long-standing customer who pays on time, orders predictably and does not cause trouble is worth keeping, and suppliers know this even when their letter does not say so. Asking - not demanding - whether there is anything available on your account, or whether the increase could be staged, or whether a commitment to volume or to shorter payment terms would change it, frequently produces something. Not always, and rarely the whole increase, but the cost of asking is one email and the answer is occasionally surprising.
The second question is the one that matters more and gets asked less: what does this do to your own prices. A business that absorbs a series of supplier increases without adjusting its own prices is slowly converting its margin into a subsidy, and because each individual increase is small, there is never a moment that forces the recalculation. Two years later the same work is being done for materially less money, and the cause is invisible because it arrived in twelve small pieces. The supplier's letter is, at minimum, a prompt to recalculate what your own work now costs to deliver.
It is also worth knowing what the increase actually applies to, because a percentage on a headline rate and a percentage across everything are different things, and announcements are not always precise. Check it against the next few invoices rather than assuming. If the rise is significant and the supplier will not move, that is the moment to find out what an alternative would genuinely cost - not necessarily to switch, since switching has costs of its own that are easy to underestimate, but to know. A business that has no idea what its alternatives look like is not choosing to stay with a supplier; it is simply staying.