Silence is usually not a no
The common reasons are boring: they are collecting quotes and yours arrived in the middle, the decision is not theirs alone, the job is not urgent yet, or life happened. None of these is an opinion about you, and none is resolved by explaining your quote again.
A real no is rare enough that assuming it is a poor default. The customer who has decided against you usually says so — saying so is easier than being followed up on.
Send something new, not a reminder
"Just checking in" is a message about you. Something the customer did not have before is a message about them: a slot that just opened, a detail about how the job actually goes, the one thing that makes your number lower than it looks next to a cheaper one.
One useful sentence beats three polite ones. If you cannot think of anything to add, that is a sign the follow-up is for your peace of mind rather than their decision.
Decide the stopping rule before you start
Two or three touches over a few days, then stop. The rule matters less than having one: without it, the decision to send another message is made by whoever is most anxious that week.
The last message should close cleanly — say you will leave it with them and that they can reply any time. That sentence does more for a reply three weeks later than any amount of chasing does this week.