Some of us are working on more complicated data than just handwritten digits. Part of the problem is that existing networks are tuned for the dataset that the o

Some of us are working on more complicated data than just handwritten digits. Part of the problem is that existing networks are tuned for the dataset that the original authors were working on. If you want to use it on completely different problems, you have to change the sizes of the layers, convolution size, max pooling, etc. The other problem is figuring out how to preprocess your data to make it as easy as possible for the network to digest. Then, to make it harder, changing the preprocessing means you have to change the network architecture, and vice versa. Fun times!