Background: In ILD Forced Vital Capacity (FVC) is reproducible and reliable (Althobiani et al 2021) and home spirometry opportunities are increasing. Knowledge of patients' use of this technology and their experiences over time is limited. We report on 6-month follow up data. Aim: To capture sequential experiences of patients with ILD using home spirometry in a UK regional ILD centre. Methods: Patients engaged in our supported self-management programme consented to participate in digital, recorded, serial, semi-structured interviews. Transcripts were analysed thematically. Results: Ten patients (8 male; median age 66y, range 50-82y; 7=IPF, 2=CTD-ILD, 1=Drug-induced ILD) completed 4 interviews over 6-months. Analysis identified 6 themes: 1) Anticipated Benefits: FVC results are useful to monitor change, trigger action or understand condition. Some expressed frustration in not fully understanding results or that in response to decline only limited action is possible. 2) Simplicity: Ease with practicalities of home spirometry increased over 6-months. 3) Technical issues: Ebbed over time. 4) Technique: Issues peaked at 1-month, reducing significantly by the final time point. 5) Physical Effort: At final time point - particular difficulties in using the spirometer when unwell resulted in avoidance. 6) Worry: A significant theme for all participants and time points. Further, anticipating or performing spirometry or viewing results caused unexpected anxiety or low mood. Conclusion: Ease with home spirometry increases over time. Anticipated benefits are not always realised. Worry is a significant issue. Re-assessment of how positive elements of home spirometry offset the negative is needed.