There is no one-size-fits-all answer to this question, as the amount of money and time you should spend on maintenance for your transport business will vary depending on the size and complexity of your business, as well as the type of vehicles and equipment you use.
However, it's a good idea to allocate a certain amount of your budget to maintenance and repairs and to set aside a certain amount of time each week or month to perform routine maintenance tasks.
Ideally, you should allocate around 10% of your income for transport business maintenance and spend at least 8 hours per week on maintenance tasks.