1 INTRODUCTION
2 GALAXY GROUP FINDING
2.1 The L-Galaxies SAM
2.2 The fidelity of recovered galaxy groups
2.3 FoF group-finder
2.4 "Halo-based" galaxy group-finder
2.5 $M_{\mathrm{H}}$-estimator
3 SCIENCE METRICS FOR PERFORMANCE ESTIMATION
3.1 Masses of the recovered groups on a galaxy basis
3.2 The recovered 2-way matched groups
3.3 Scatter in $M_{\mathrm{H}}$
3.4 Metrics for Central/Satellite classification
3.5 Number of groups and multiplicity
4 PERFORMANCE OF "HALO-BASED" AND FoF METHODS AT LOW REDSHIFT
5 PERFORMANCE OF FoF CATALOGUES AT HIGH REDSHIFT IN $s/M_{\mathrm{star}}$-SPACE
5.1 The redshift range $1.2<z<1.7$
5.2 The variation with redshift
5.3 Science example: Quenching fractions
6 SURVEY COSTS ANALYSIS IN $\textbf{N}s/M_{\mathrm{star}}$-SPACE
6.1 Breakdown of survey costs
6.2 Generic survey design considerations in $s/M_{\mathrm{star}}$-space
6.3 The efficiency factor $\epsilon$ of MOONS in $s/M_{\mathrm{star}}$-space
7 SUMMARY AND CONCLUSION