What are the disadvantages of paging and segmentation?

Paging can lead to internal fragmentation, where allocated memory may not be fully utilized, as pages are fixed-size blocks. Segmentation, while allowing for variable-sized blocks, can suffer from external fragmentation as segments grow and shrink, potentially wasting memory space. Additionally, both methods can introduce overhead in managing the page table or segment table, impacting performance. Lastly, the combination of both techniques can complicate memory management further.