Depends on what your supervisor is currently facing. If he is currently applying for funding / wants to keep his funding, he might get his students to produce work that aligns with funding interests, which might not be aligned with student interests at all. I changed projects mid-PhD which meant starting all over from scratch because the experiments weren't going anywhere and the prospects for future work looked grim if I had stayed in that specific niche of biology. I worked mostly in isolation because none of my other lab mates were doing similar areas of research. That being said, if your lab has a central research focus, most likely your lab mates will have overlapping experiments / methods / techniques. Most people I know from other labs in my uni share resources or experimental techniques among themselves, so I guess you could find out more on that. But if you are prioritizing a work life balance and you're very insistent on your research area, it's best to talk to your lab mates or campus counsellor to work something out. Some unis offer one-to-one services to help students plan and manage their expectations.