Should I buy a single stick of DDR5 RAM for future expansion or get a dual-channel kit now?

Buy the dual-channel kit now. Running a single stick of DDR5 halves memory bandwidth, costing 30-40% performance in games and memory-sensitive tasks. If you need 64GB later, buy a 2x16GB kit now, then sell it and swap to 2x32GB. Mixing a single stick later risks instability and lower speeds due to DDR5’s finicky memory training.