There are two sources of money for any business: 1) revenue or 2) anything else.
Our ability to hire additional people has always been fueled by revenue growth. We had a few small investments early on, enough to pay our rent but not our credit cards. In the early days, before significant revenue, we wished we had investment so we could hire faster.
Hindsight makes us glad we didn't raise more money. Having a limited budget made us extremely careful with hiring, both in deciding hiring priorities and in choosing who joins our team.
We now find growing off revenue makes us more attractive to potential hires. When things get serious with a candidate, one of the questions they usually ask is how likely it is our funding will go away. Often, they or someone they know has experienced a startup laying off staff due to investment drying up. They're always happy to learn we've been growing off revenue for years.