When my kids were babies I would change their clothes once per day unless they threw up on the clothes or had a diaper blowout or had a wet diaper leak.
Some days the baby could go a whole day wearing the same clothes and then the next day the baby would need to be changed into fresh clothes 3 times per day.
If you keep check on the babies diaper though and change it before it has a time to leak urine then the baby will only need a diaper change and not need their pants changed.
I always kept spare clothes in the car and spare diapers so that I would always have clean clothes and clean diapers.
When my son was 3 years old he wet his diaper while we were out at the park and the diaper leaked and soaked the front and back of his pants while he was sitting down at the picnic table.
I had no change of clothes for him but did have clean diapers and so after I changed his diaper there on the picnic table he went the rest of the day at the park wearing just his diaper and shirt and shoes.
He didn't seem to mind it but if it were cold out we would have had to go home.
But it was hot outside so it was okay for him to be in just his diaper.