Because there are some types of malfunctions where troubleshooting and repairing it is a much more complex process than replacing a battery. For example, repairing glued appliances, where only disassembly, then gluing and drying only takes 2-3 hours extra. But this can be a software failure, for example, where you need to save up to GB of data for hours and then restore everything after repair. The repair time of a soaked appliance, before we exclude any faults, can take up to a week in the worst case. Or a device that doesn't charge, for example. In this case, we replace the battery or a charging connector and then perform dive and charge tests directly. Only these tests take 1-2 days. If it still doesn't charge or dives fast, let's look at the motherboard level. Charge controller IC, PM IC possibly. Replacing these alone can take 2-3 hours under the microscope. Then the dive and charge test again. Another 1-2 days. For many devices, we need to start by restoring the software to the factory, which requires a backup and then restoring it at the end of the repair. Nowadays, one can be up to 50-60 GB or more, which can also be measured in hours. But it may also be that the part you are waiting for is out of stock. For individual purchases, this can take up to 1 month, but usually takes 1-2 weeks to resolve. If these cases add up, it can really delay the repair. To sum it all up, we will do our best to keep the time as short as possible, because then we are in the best interest of ours. Needless to say, we don't sit on appliances, because it won't heal itself.