Answer:
1st one is no. Maintenance expenses do not add any value to the asset and the useful life does not change because of such improvements. Moreover, this has no impact on the depreciation too.
2nd one is yes. It should be capitalised as it directly increases the useful life time of the asset. This suggest that the improvement also changes the productivity of the asset and has an impact on the depreciation as well.
3rd one is Yes as well. When the "utility" of an asset is increased, this suggest that it's ability to generate future cash flows has also increased as well. Because of that, the expenditure must be capitalised and the useful life and the depreciation has to be adjusted accordingly as necessary.
Step-by-step explanation: